[PATCH 21.5] -Wdeclaration-after-statement support

PATCH 21.5 This patch captures the values of __GNUC__ and __GNUC_MINOR__ in configure variables when gcc is used. It uses them to see if gcc 3.4 or later is in use and, if so, adds -Wdeclaration-after-statement to the warning flags when compiling with C. I am interested in finding out whether this approach is acceptable to the other developers. In particular, is the $(( ... )) syntax okay? It is standard Bourne shell (see the Single Unix Specification on www.unix.org), but it is not used anywhere in our present configure script. Is anyone using a shell that does not support that syntax? ChangeLog addition: 2006-06-20 Jerry James <james(a)xemacs.org&gt; * configure.ac: When gcc is used, capture the values of __GNUC__ and __GNUC_MINOR__. Use them to conditionally add warning flags that are not supported by all versions of gcc. xemacs-21.5 source patch: Diff command: cvs -q diff -uN Files affected: configure.ac Index: configure.ac =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/configure.ac,v retrieving revision 1.43 diff -d -u -r1.43 configure.ac --- configure.ac 2006/06/06 00:18:29 1.43 +++ configure.ac 2006/06/20 17:11:33 ＠＠ -1883,15 +1883,13 ＠＠ dnl Determine GCC version. if test "$GCC" = "yes"; then AC_RUN_IFELSE([AC_LANG_SOURCE([int main () { -#if __GNUC__ >= 3 -return 11; -#else -return 0; -#endif -}])], [:], -[case "$?" in - 11) echo "You appear to be using GCC version 3 or above."; __GCC3=yes ;; -esac]) +return __GNUC__; +}])], [:], [__GCC="$?"]) +AC_RUN_IFELSE([AC_LANG_SOURCE([int main () { +return __GNUC_MINOR__; +}])], [:], [__GCC_MINOR="$?"]) +__GCC_VERSION=$__GCC"."$__GCC_MINOR +echo "You appear to be using GCC version" $__GCC_VERSION fi dnl Support for using a different compiler for xemacs itself. ＠＠ -2311,7 +2309,7 ＠＠ dnl Warnings about char subscripts are pretty pointless, though, dnl and we use them in various places. with_cflags_warning="$with_cflags_warning -Wsign-compare -Wno-char-subscripts" - test "$__GCC3" = "yes" && with_cflags_warning="$with_cflags_warning -Wpacked" + test $((__GCC)) -ge 3 && with_cflags_warning="$with_cflags_warning -Wpacked" dnl glibc is intentionally not `-Wpointer-arith'-clean. dnl Ulrich Drepper has rejected patches to fix the glibc header files. test "$have_glibc" != "yes" && \ ＠＠ -2327,8 +2325,11 ＠＠ dnl some very ugly code changes. if test "$with_xemacs_compiler" = "g++"; then xe_cflags_warning="$with_cflags_warning -Weffc++" - elif test "$__GCC3" = "yes"; then + elif test $((__GCC)) -ge 3; then xe_cflags_warning="$with_cflags_warning -Wunused-parameter" + if test $((__GCC)) -gt 3 || test $((__GCC_MINOR)) -ge 4; then + with_cflags_warning="$with_cflags_warning -Wdeclaration-after-statement" + fi fi with_cflags_warning="$with_cflags_warning -Wshadow -Wmissing-declarations" with_cflags_warning="$with_cflags_warning -Wmissing-prototypes -Wstrict-prototypes" -- Jerry James, Assistant Professor james(a)xemacs.org Computer Science Department http://www.cs.usu.edu/~jerry/ Utah State University