Hi I currently have 21.4.15, but for what ever reason my installation does not have a subr.el file, which has the add-to-invisibility-spec function that I need to use. To overcome this deficiency, I downloaded Xemacs 21.5, and was attempting to build it from source through this package: http://ftp.xemacs.org/xemacs-21.5/xemacs-21.5.0.tar.gz Two problems here: 1. Although this file has a subr.el, it does not have the add-to-invisibility-spec that I desperately need. 2. When I try to build, I bomb out on the ./configure step with : configure:3220: gcc -o conftest -g -O3 -Wall -Wno-switch -Winline -Wmissing-prototypes -Wshadow -Wsign-compare -L/usr/lib64 -Xlinker -rpath -Xlinker /usr/lib64 conftest.c -lgcc -lc -lgcc /usr/lib/crtn.o 1>&5 and configure:3450:28: error: cygwin/version.h: No such file or directory configure:3450:23: error: mach/mach.h: No such file or directory This is on a X86-64 RedHat system I tried specifying /usr/lib64 as the --site-libraries and --site-runtime-libraries, but with no noticeable effect based on config.log. My needs are fairly straight-forward. I need to get add-to-invisibility-spec working so that I might get the hide-lines.el (another script) working. Can I get that going on my existing 21.4.15? If not how can I overcome the above and get 21.5 working with add-to-invisibility-spec (given that this function is not defined in subr.el, although it is defined in a file of the same name in my emacs installation)? Thanks RAvindra