CVS update by malcolmp MODIFIED: xemacs/man/internals ...

User: malcolmp Date: 05/03/10 12:44:24 Modified: xemacs/man/internals internals.texi Log: Autoconf 2.5 documentation updates. Revision Changes Path 1.292 +7 -0 XEmacs/xemacs/man/ChangeLog Index: ChangeLog =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/man/ChangeLog,v retrieving revision 1.291 retrieving revision 1.292 diff -u -r1.291 -r1.292 --- ChangeLog 2005/03/09 05:36:28 1.291 +++ ChangeLog 2005/03/10 11:44:17 1.292 ＠＠ -1,3 +1,10 ＠＠ +2005-03-05 Malcolm Purvis <malcolmp(a)xemacs.org&gt; + + * beta.texi : Change configure arguments to the new autoconf 2.5 + style configure. + * internals/internals.texi (The Build Configuration System): Fill + out the details. + 2005-01-19 Aidan Kehoe <kehoea(a)parhasard.net&gt; * lispref/mule.texi (CCL Example): Detail an implementation of the 1.3 +42 -35 XEmacs/xemacs/man/beta.texi Index: beta.texi =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/man/beta.texi,v retrieving revision 1.2 retrieving revision 1.3 diff -u -r1.2 -r1.3 --- beta.texi 2005/02/03 06:14:40 1.2 +++ beta.texi 2005/03/10 11:44:17 1.3 ＠＠ -377,10 +377,9 ＠＠ It's a good idea to use ＠example ---extra-verbose ---debug ---memory-usage-stats ---error-checking=all +--enable-debug +--enable-memory-usage-stats +--enable-error-checking=all ＠end example These turn on extra debugging info and checks. The last one in particular ＠＠ -392,10 +391,10 ＠＠ You should also strongly consider ＠example ---with-mule ---use-pkcc ---pdump ---with-clash-detection +--enable-mule +--enable-kkcc +--enable-pdump +--enable-clash-detection --with-wmcommand --with-xfs ＠end example ＠＠ -406,8 +405,8 ＠＠ If you have gcc, consider using ＠example ---compiler=gcc ---xemacs-compiler=g++ +--with-compiler=gcc +--with-xemacs-compiler=g++ ＠end example This will compile XEmacs using g++, which will turn on a lot of additional ＠＠ -418,7 +417,7 ＠＠ line like ＠example ---package-path=~/.xemacs::/xemacs/site-packages:/xemacs/xemacs-packages:/xemacs/mule-packages +--with-package-path=~/.xemacs::/xemacs/site-packages:/xemacs/xemacs-packages:/xemacs/mule-packages ＠end example ＠item ＠＠ -435,12 +434,12 ＠＠ populate your build directory. ＠item -Use --site-prefixes (or --site-includes and --site-libraries) if you have -some packages that XEmacs can compile with that are located in an unusual -place. For example: +Use --with-site-prefixes (or --with-site-includes and +---with-site-libraries) if you have some packages that XEmacs can +compile with that are located in an unusual place. For example: ＠example ---site-prefixes=/usr/local/pgsql:/usr/local/BerkeleyDB.4.1 +--with-site-prefixes=/usr/local/pgsql:/usr/local/BerkeleyDB.4.1 ＠end example ＠item ＠＠ -455,33 +454,41 ＠＠ the command ＠kbd{M-x describe-installation RET}). ＠example -uname -a: Linux eicq 2.4.20 #1 Wed Dec 18 02:14:29 EST 2002 i586 unknown +uname -a: Darwin laptop.local 7.7.0 Darwin Kernel Version 7.7.0: Sun Nov 7 16:06:51 PST 2004; root:xnu/xnu-517.9.5.obj~1/RELEASE_PPC Power Macintosh powerpc -./configure '--extra-verbose' '--site-prefixes=/usr/local/pgsql:/usr/local/BerkeleyDB.4.1' '--dynamic=yes' '--with-gtk=no' '--with-gnome=no' '--with-toolbars' '--with-wmcommand' '--with-athena=next' '--with-menubars=lucid' '--with-scrollbars=athena' '--with-dialogs=athena' '--with-widgets=athena' '--with-gif' '--with-sound=native,noesd' '--with-site-lisp=no' '--with-site-modules' '--pdump' '--with-mule' '--with-xfs' '--debug' '--error-checking=all' '--memory-usage-stats' '--use-kkcc' '--with-clash-detection' +./configure '--with-site-prefixes=/sw' '--without-ldap' '--with-dynamic=yes' '--with-gtk=no' '--with-gnome=no' '--enable-toolbars' '--with-wmcommand' '--with-athena=3d' '--enable-menubars=lucid' '--enable-scrollbars=athena' '--enable-dialogs=athena' '--enable-widgets=athena' '--with-gif' '--enable-sound=native,noesd' '--with-site-lisp=no' '--with-site-modules' '--enable-pdump' '--enable-mule' '--with-xfs' '--enable-debug' '--enable-error-checking=all' '--enable-memory-usage-stats' '--enable-kkcc' '--enable-clash-detection' -XEmacs 21.5-b10 "burdock" (+CVS-20030131) configured for `i586-pc-linux'. +XEmacs 21.5-b19 "chives" (+CVS-20050226) configured for `powerpc-apple-darwin7.7.0'. + WARNING: -------------------------------------------------------------- + WARNING: This was produced from a new autoconf-2.5 based configuration. + WARNING: If this configuration seems buggy then copy etc/configure-2.13 + WARNING: to configure and try again. Also please report the bug. + WARNING: -------------------------------------------------------------- -Compilation / Installation: +Compilation Environment and Installation Defaults: Source code location: /usr/local/src/xemacs Installation prefix: /usr/local - Additional prefixes: /usr/local/pgsql /usr/local/BerkeleyDB.4.1 - Operating system description file: `s/linux.h' - Machine description file: `m/intel386.h' - Compiler: gcc -Wall -Wno-switch -Winline -Wmissing-prototypes -Wsign-compare -Wundef -Wstrict-prototypes -Wshadow -Wmissing-declarations -O1 -ggdb3 -Wall -Wchar-subscripts -Wunused -Wundef -Wshadow -Wsign-compare -Wmissing-declarations -march=k6 + Additional prefixes: /sw + Operating system description file: `s/darwin.h' + Machine description file: `m/powerpc.h' + Compiler version: gcc (GCC) 3.3 20030304 (Apple Computer, Inc. build 1671) + - GCC specs file: /usr/libexec/gcc/darwin/ppc/3.3/specs + - Compiler command: gcc -Wall -Wno-switch -Wundef -Wsign-compare -Wno-char-subscripts -Wpacked -Wpointer-arith -Wunused-parameter -g + libc version: Relocating allocator for buffers: no - GNU version of malloc: yes - - Using Doug Lea's new malloc from the GNU C Library. + GNU version of malloc: no + - The GNU allocators don't work with this system configuration. Window System: Compiling in support for the X window system: - - X Windows headers location: /usr/X11/include - - X Windows libraries location: /usr/X11/lib + - X Windows headers location: /usr/X11R6/include + - X Windows libraries location: /usr/X11R6/lib - Handling WM_COMMAND properly. Compiling in support for the Athena widget set: - - Athena headers location: X11/neXtaw - - Athena library to link: neXtaw + - Athena headers location: X11/Xaw3d + - Athena library to link: Xaw3d Using Lucid menubars. Using Athena scrollbars. Using Athena dialog boxes. ＠＠ -489,7 +496,6 ＠＠ TTY: Compiling in support for ncurses. - Compiling in support for GPM (General Purpose Mouse). Images: Compiling in support for GIF images (builtin). ＠＠ -500,12 +506,12 ＠＠ Compiling in support for X-Face message headers. Sound: - Compiling in support for sound (native). Databases: Compiling in support for Berkeley database. + Compiling in support for GNU DBM. Compiling in support for PostgreSQL. - - Using PostgreSQL header file: libpq-fe.h + - Using PostgreSQL header file: postgresql/libpq-fe.h - Using PostgreSQL V7 bindings. Internationalization: ＠＠ -515,7 +521,7 ＠＠ - Using XFontSet to provide bilingual menubar. Mail: - Compiling in support for "dot-locking" mail spool file locking method. + Compiling in support for "file" mail spool file locking method. Other Features: Inhibiting IPv6 canonicalization at startup. ＠＠ -523,10 +529,11 ＠＠ Using the new GC algorithms. Using the new portable dumper. Compiling in support for extra debugging code. - WARNING: WARNING: Compiling in support for runtime error checking. + Compiling in support for runtime error checking. + WARNING: --------------------------------------------------------- WARNING: XEmacs will run noticeably more slowly as a result. WARNING: Error checking is on by default for XEmacs beta releases. - WARNING: + WARNING: --------------------------------------------------------- ＠end example ＠end enumerate 1.62 +134 -92 XEmacs/xemacs/man/internals/internals.texi Index: internals.texi =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/man/internals/internals.texi,v retrieving revision 1.61 retrieving revision 1.62 diff -u -r1.61 -r1.62 --- internals.texi 2005/03/09 05:36:35 1.61 +++ internals.texi 2005/03/10 11:44:22 1.62 ＠＠ -4159,12 +4159,11 ＠＠ ＠cindex build configuration ＠cindex configuration, build -＠strong{Please write this node!} ＠c #### +XEmacs makes extensive use of the external features provided by the +system it is running on. Determining which features are present and +where they are located is the responsibility of the build configuration +system. -This node should describe XEmacs-specific techniques and idioms in the -configuration system. A particular example is the set of ＠samp{XE_} -macros in ＠file{configure.in} and ＠file{configure.ac}. - ＠menu * The version.sh Script:: * Adding Configurable Features:: ＠＠ -4270,12 +4269,18 ＠＠ ＠cindex adding configurable features ＠cindex configurable features, adding ＠cindex features, adding configurable - -Adding a configurable feature requires at least adding an option to the -＠file{configure} script and a macro definition to ＠file{src/config.h.in} -(＠pxref{The configure Script}), and often changes to Makefile precursors -(＠pxref{The Makefile Precursors}). +Adding a configurable feature requires at the very least adding an +option to the ＠file{configure} script and a macro definition to +(a)file{src/config.h.in} (＠pxref{The configure Script}), and often changes +to Makefile precursors (＠pxref{The Makefile Precursors}). + +Be prepared for the feature to be absent (even if you think that is +always present for a particular OS release) and work with +＠code{--with-site-prefixes} to handle libraries and headers that are in +unusual locations. There is no end to the strange ways in which systems +can be configured and XEmacs is expected to cope with anything thrown at +it. ＠node The configure Script, The Makefile Precursors, Adding Configurable Features, The Build Configuration System ＠＠ -4286,26 +4291,37 ＠＠ At the heart of the XEmacs build configuration system is the ＠file{configure} script. This beast is maintained using the Autoconf system, which is a truly terrifying monstrosity based on a fundamentally -flawed programming model (extensive use of macros), with an -implementation about which I've never heard a nice word (GNU ＠file{m4}), -used to string together a large set of ＠emph{ad hoc} tests, to implement -a configuration language with conventions that are unimportant in simple -cases and counterintuitive when things get complicated. If that doesn't -scare you off, Welcome! I think you're ready to become a configure -hacker! (But be prepared for things to go downhill from here.) +flawed programming model (extensive use of macros), with an unpleasant +implementation (GNU ＠file{m4}), used to string together a large set of +＠emph{ad hoc} tests, to implement a configuration language with +conventions that are unimportant in simple cases and counterintuitive +when things get complicated. If that doesn't scare you off, Welcome! I +think you're ready to become a configure hacker! (But be prepared for +things to go downhill from here.) + +Unless you plan to develop autoconf macros, much of this complexity can +be removed by following the following rule: + +＠quotation +Always quote (ie surround with ＠samp{[]}) every argument to every +macro. This includes macros that appear in the argument list of other +macros. +＠end quotation + +If this rule is followed and the macro produces incorrect results then +the macro is buggy. ＠file{configure} is, of course, is written in POSIX shell language, and -autogenerated from a precursor (see? the first step was a doozy!) -Currently that precursor is called ＠file{configure.ac}, but in the -previous generation it was called ＠file{configure.in}. As of February -2005, ＠file{configure.ac} is used in the development mainline, but -because the semantics of many predefined macros changed drastically -between ＠file{autoconf} 2.13 and ＠file{autoconf} 2.50 (why not ``3.0''? -you got me), the XEmacs Project chose to stick with the devil it knew -for the stable line of XEmacs 21.4 releases. +autogenerated from a precursor. As of March 2005 on the mainline the +precursor is called ＠file{configure.ac} and it is built using +＠code{autoconf} 2.59. Prior to that, and with XEmacs 21.4 and earlier +it was called ＠file{configure.in} and build using ＠code{autoconf} 2.13. +＠code{autoconf} 2.5X is not completely backward compatible with +＠code{autoconf} 2.13 so the XEmacs Project chose to stick with the devil +it knew for the stable line of XEmacs 21.4 releases. -One reason for worrying about the semantic changes is the fact that -XEmacs uses a lot of homebrew code, including ＠file{m4} macros, to +One reason for worrying about the level of compatibility is the fact +that XEmacs uses a lot of homebrew code, including ＠file{m4} macros, to implement special features in its ＠file{configure} script. Here are some of the important features: ＠＠ -4326,85 +4342,116 ＠＠ ＠c #### ＠var{}-ize the formal parameters of these functions? ＠table ＠code ＠item USAGE_ERROR(string) -prints a usage error and dies +Prints a usage error and dies. ＠item PRINT_VAR(var var ...) -prints values of shell variables +Prints the name and value of the list of shell variables. -＠item XE_ADD_OBJS(foo.o ...) -＠strong{#### Please document me!} +＠item XE_ADD_OBJS(foo.o) +Appends the argument to the variable ＠code{extra_objs}. This variable +goes to make up part of the link command line. If the command line +argument ＠code{--verbose} is supplied a message is printed out. ＠item XE_APPEND(value, varname) -＠strong{#### Please document me!} +Append the value (separated by a space) to the shell variable +＠var{varname}. ＠var{varname} should not be prefixed with a ＠samp{$}. +If the command line argument ＠code{--verbose} is supplied a message is +printed out. ＠item XE_PREPEND(value, varname) -＠strong{#### Please document me!} +Prepend the value (separated by a space) to the shell variable +＠var{varname}. ＠var{varname} should not be prefixed with a ＠samp{$}. +If the command line argument ＠code{--verbose} is supplied a message is +printed out. ＠item XE_DIE(message) -used for situations that can't lead to a successful build, such as +Used for situations that can't lead to a successful build, such as missing include files or conflicts between requested features. ＠item XE_CHECK_FEATURE_DEPENDENCY(feature1, feature2) -＠strong{#### Please document me!} +＠code{--with-＠var{feature1}} requires that ＠code{--with-＠var{feature2}} +be also set and will die if the latter is not specified. ＠item XE_STRIP_4TH_COMPONENT(var) -＠strong{#### Please document me!} +Converts the four part system name (eg ＠code{i986-pc-linux-gnu}) in +＠var{var} to a three part names (eg ＠code{i986-pc-linux}). ＠item CANONICALIZE_PATH(varname) -＠strong{#### Please document me!} +Strips automount brokenness from the path in ＠var{varname}. ＠item XE_PROTECT_LINKER_FLAGS(shell_var) -＠strong{#### Please document me!} +Wrap the command line arguments in ＠var{shell_var} with suitable +incantations to ensure that the compiler front end passes them to the +linker. Currently the magic is added only for gcc. ＠item COLON_TO_SPACE(path) -Allow use of either ＠samp{:} or spaces for lists of directories. +Converts a colon separated list of paths into a space separated list of paths. ＠item XE_ADD_RUNPATH_DIR(directory) -＠strong{#### Please document me!} +Internal function used by ＠code{XE_COMPUTE_RUNPATH}. ＠item XE_COMPUTE_RUNPATH() -＠strong{#### Please document me!} +Calculate the appropriate dynamic library run path for XEmacs and the +value to the shell variable ＠code{ld_switch_run}. ＠item XE_SPACE(var, words) -＠strong{#### Please document me!} +Append to ＠code{var} a space separated list of ＠code{words}. ＠item XE_SHLIB_STUFF -See ＠file{aclocal.m4}. +Generate the appropriate shared library support black magic. This is +implemented in the file ＠file{aclocal.m4}. ＠end table ＠heading XEmacs keyword option support A ＠dfn{keyword} option is one that accepts one of a number of -pre-defined values (if support for sets of values is needed, see +pre-defined values (if support for sets of values is needed, x1see ``complex options'' below). For example, ＠samp{--with-mail-locking=flock}. -Keyword options use expanded forms of ＠samp{AC_ARG_[WITH|ENABLE]} called -＠samp{XE_KEYWORD_ARG_[WITH|ENABLE]}, both taking 5 parameters. The -first 4 parameters of these macros are the same as original macros with -the exception that all four parameters are ＠strong{required}. The -＠var{action-if-true} code is run after the argument list has been -parsed. +Keyword options are defined with expanded forms of +＠samp{AC_ARG_[WITH|ENABLE]} called ＠samp{XE_KEYWORD_ARG_[WITH|ENABLE]}, +both taking 5 parameters. The first 4 parameters of these macros are +the same as original macros with the exception that all four parameters +are ＠strong{required}. The ＠var{action-if-true} code is run after the +argument list has been parsed. The 5th parameter is a list of supported keywords. The whole list must -be quoted but the individual keywords should not. +be quoted but the individual keywords should not. Here is how the +＠samp{mail-locking} flag is defined: + +＠example +XE_KEYWORD_ARG_WITH([mail-locking], + AC_HELP_STRING([--with-mail-locking],[Specify the locking to be + used by movemail to prevent concurrent updates + of mail spool files. Valid types are `lockf', + `flock', `dot', `locking' or `mmdf'.]), + [], + [], + [lockf,flock,file,locking,mmdf,pop]) +＠end example +(Note that the help string will be reformatted by ＠file{autoconf} so +that all whitespace is first compressed to a single space, then folded +to appear in the right-hand column as above. Thus the help string may +appear differently when ＠code{./configure --help} is invoked.) + If the option value is a not a valid keyword then an error message is generated, otherwise the value is left untouched. This support is implemented via the following ＠file{GNU m4} macros. -Macros labelled ＠dfn{internal} are not expected to be used by +Macros labeled ＠dfn{internal} are not expected to be used by ＠file{configure.ac} programmers; they are part of the implementation of higher-level features. ＠table ＠code ＠item XE_KEYWORD_ARG_WITH(package, help-string, action-if-true, action-if-false, [keyword1, keyword2, ....]) -Expanded version of ＠samp{AC_ARG_WITH} for keyword options. All the +Expanded version of ＠code{AC_ARG_WITH} for keyword options. All the parameters are required. The last argument is a comma-separated list of supported keywords, ＠file{m4}-quoted with ＠samp{[]}. ＠item XE_KEYWORD_ARG_ENABLE(feature, help-string, action-if-true, action-if-false, [keyword1, keyword2, ....]) -Expanded version of ＠samp{AC_ARG_ENABLE} for keyword options. All the +Expanded version of ＠code{AC_ARG_ENABLE} for keyword options. All the parameters are required. The last argument is a comma-separated list of supported keywords, ＠file{m4}-quoted with ＠samp{[]}. ＠＠ -4413,26 +4460,25 ＠＠ found then an error is generated. ＠item XE_KEYWORD(keyword) -Internal macro to declare an option value. +Internal macro to convert the keyword list into the various forms needed +by ＠code{XE_PARSE_KEYWORD_OPTION}. ＠end table ＠heading XEmacs complex option support A ＠dfn{complex option} is one that takes a number of related values, as -a set. For example, we might use "--with-xft=all,nomenubars" for -compatibility with XFontSet i18n of menubars. (The example is -contrived, Xft looks much better than XFS.) Processing such an option -requires a number of auxiliary variables. - -Complex options use expanded forms of ＠samp{AC_ARG_[WITH|ENABLE]} called -＠samp{XE_COMPLEX_ARG_[WITH|ENABLE]}, both taking 5 parameters. The -first 4 parameters of these macros are the same as original macros with -the exception that all four parameters are ＠strong{required}. The -＠var{action-if-true} code is run after the argument list has been -parsed. +a set. For example, we might use ＠code{--with-sound=native,nas} to play +sounds using the native libraries and via NAS. + +Complex options are defined with expanded forms of +＠samp{AC_ARG_[WITH|ENABLE]} called ＠samp{XE_COMPLEX_ARG_[WITH|ENABLE]}, +both taking 5 parameters. The first 4 parameters of these macros are +the same as original macros with the exception that all four parameters +are ＠strong{required}. The ＠var{action-if-true} code is run after the +argument list has been parsed. -The 5th parameter is a list of ＠samp{XE_COMPLEX_OPTION} macro calls that +The 5th parameter is a list of ＠code{XE_COMPLEX_OPTION} macro calls that define the valid components and their default values. The list must be quoted but the individual macro calls should not. Here is how the ＠samp{sound} flag is defined: ＠＠ -4454,23 +4500,18 ＠＠ XE_COMPLEX_OPTION([esd],[no])]) ＠end example -(Note that the help string will be reformatted by ＠file{autoconf} so -that all whitespace is first compressed to a single space, then folded -to appear in the right-hand column as above. Thus the help string may -appear differently when ＠code{./configure --help} is invoked.) - ＠c #### verify for INSTALL and xemacs Texinfo. -Each component is interpreted as a separate feature to be enabled or +Each option is interpreted as a separate feature to be enabled or disabled. As usual, the distinction between ``with'' and ``enable'' is that ``with'' features require specific support from the system, usually one or more optional libraries, and ``enable'' features are supported entirely by code in XEmacs, but the user might want to switch it off for some reason. Option values are stored in the variables -＠samp{with_＠var{package}_＠var{component}} or -＠samp{enable_＠var{feature}_＠var{component}} (＠i{e.g.} -＠samp{with_xft_menubars}). +＠code{with_＠var{package}_＠var{component}} or +＠code{enable_＠var{feature}_＠var{component}} (＠i{e.g.} +＠code{enable_sound_native}). -The user of ＠file{configure} specifies the configuration by providing a +The user of ＠code{configure} specifies the configuration by providing a list of components. The special components ＠samp{all} and ＠samp{none} may occur first in the list, setting the defaults for all components to ＠samp{yes} or ＠samp{no} respectively. ＠＠ -4482,7 +4523,7 ＠＠ value can also be the null string ＠samp{""}, usually meaning that ＠file{configure} will attempt to find support for the feature on the system, and will enable the configuration if it is available. Sometimes -the null string means that ＠file{configure}'s default is +the null string means that ＠code{configure}'s default is system-dependent. (This usage is not consistent, and depends on the implementation of the feature detector rather than the argument parser.) Users cannot specify the null string for an individual component from ＠＠ -4494,7 +4535,7 ＠＠ library which may or may not be supported by multiple components of XEmacs, as exemplified by Xft. This latter usage may be more common during development of a feature. Perhaps specialized APIs should be -provided, see comment on ＠samp{XE_COMPLEX_OPTION_HELP_STRING} below. +provided, see comment on ＠code{XE_COMPLEX_OPTION_HELP_STRING} below. ＠table ＠code ＠item XE_COMPLEX_OPTION(option, yesno) ＠＠ -4513,11 +4554,11 ＠＠ the API may be enhanced to deal with this in the future. ＠item XE_COMPLEX_ARG_WITH(PACKAGE, HELP-STRING, ACTION-IF-TRUE, ACTION-IF-FALSE, [XE_COMPLEX_OPTION(a,yes), ....]) -Extended version of ＠samp{AC_ARG_WITH} for complex options. All the +Extended version of ＠code{AC_ARG_WITH} for complex options. All the parameters are required. ＠item XE_COMPLEX_ARG_ENABLE(FEATURE, HELP-STRING, ACTION-IF-TRUE, ACTION-IF-FALSE, [XE_COMPLEX_OPTION(a,yes), ....]) -Expanded version of ＠samp{AC_ARG_ENABLE} for complex options. All the +Expanded version of ＠code{AC_ARG_ENABLE} for complex options. All the parameters are required. ＠item XE_EXPAND_COMPLEX_OPTION(prefix, component, yesno) ＠＠ -4548,21 +4589,22 ＠＠ ＠cindex Makefile precursors ＠cindex precursors, Makefile -＠strong{Please write this node!} ＠c #### - -As in other programs using a ＠file{configure} program, XEmacs's -Makefiles are not written, they are generated. The ＠file{configure} -program uses Makefile precursors, or templates, to generate the actual -Makefiles. In fact, it is a multistage process. The developer changes -the file ＠file{Makefile.in.in}, then ＠file{configure} first generates an +As with other ＠code{autoconf} based programs, XEmacs's Makefiles are not +written, they are generated. The ＠code{configure} program uses Makefile +precursors, or templates, to generate the actual Makefiles. Unlike +other programs this is a multistage process. The developer changes the +file ＠file{Makefile.in.in}, then ＠code{configure} first generates an intermediate file ＠file{Makefile.in}, and finally produces a portable -Makefile called ＠file{Makefile}, and a Makefile optimized for ＠file{GNU +Makefile called ＠file{Makefile}, and a Makefile optimized for ＠code{GNU make} called ＠file{GNUmakefile}. - -This node describes XEmacs-specific techniques and idioms used in the -(a)file{Makefile.in.in} files. +(a)file{Makefile.in.in} is run through the C preprocessor as part of this +process. This means that common files can be included and conditional +construction of the Makefile can occur. When ＠file{GNUmakefile} is +being produced ＠code{USE_GNU_MAKE} is defined. +Comments in ＠file{Makefile.in.in} must start with ＠samp{##} to avoid +confusing the preprocessor. ＠node Rules When Writing New C Code, Regression Testing XEmacs, The Build Configuration System, Top ＠chapter Rules When Writing New C Code