Bug#667184: gnat-4.6: intermittent FTBFS, race condition in Makefiles with too many parallel processes
retitle 667184 gnat-4.6: intermittent FTBFS, race condition in
severity 667184 important
usertags - ftbfs-gcc-4.7
This bug has nothing to do with gcc-4.7. Analysis of the full log file
reveals that the bootstrap used 10 parallel processes, which triggered
this race condition. Building the executable program 'gnatfind'
requires the object file xref_lib.o, which does not exist yet because
another gnatmake is still building it.
I think the problem is that make is running several gnatmake processes
parallel in the same directory (one for each tool to build). The
gnatmake processes step on each other's toes. The fix is to run the
gnatmake processes sequentially but pass the parallel option to each of
them, so they can run parallel compilations as needed.