The changes described in <http://gcc.gnu.org/ml/gcc-patches/2008-04/msg00607.html> entitled "More code clean up in mlib-tgt-*" changes/renames a number of files from the form mlib-tgt-xxxxxx.adb to mlib-tgt-specific-xxxxxx.adb. However the corresponding changes were not made to gnatlib/configure.ac. This results in a softlink from mlib-tgt-specific.adb in the tools build directory to a non-existent file. When gnatmake is built the default mlib-tgt-specific.adb file is used. Any attempt to use the new gnatmake to build against a library project results in a failure with an error message stating libraries are not supported on this platform. The fix is to change all occurrences of mlib-tgt-xxxxx.adb to mlib-tgt-specific-xxxx.adb in gnatlib/configure.ac and to regenerate gnatlib/configure. Additionally two occurrences where not updated in gcc/ada/Makefile.in (*86 kfreebsd and sh4 linux). A more interesting question (which I have not explored yet) is why the build silently ignores the bad symlink, and continues on using a default file from further down the search list.
Created attachment 15791 [details] patch to fix configuration for ada/36562 Attached is a patch which fixes configuration problem associated with the bug. This has only been tested on x86_64-linux.
Fixed in SVN trunk, thanks Chris for the patch.