Regenerate configure files using OS/2 autotools

[dmik]

The GCC policy is that they put pre-generated autotools scripts (configure, libtool, Makefile.in, aclocal.m4 and so on) in the repository. Perhaps, they do it because they have quite a lot of sub-projects and these sub-projects are quite complex in their configure part so that one needs to have a lot of experience and good luck to generate proper configure and friends.

However, since the official versions of autotools lack many bits of OS/2 support, these pre-generated scripts lack it as well. This is a source of various build issues. Since we have relatively fresh versions of almost all autotools now, we should regenerate them in our repo to make them OS/2 friendly. Sometimes we also need to tailor configure scripts for OS/2 on their own but since we don't regenerate them ATM we have to e.g. change configure instead of its source, configure.ac (or Makefile.in instead of Makefile.am) which is inconsistent and error prone.

The problem is that GCC insists on the particular version of autoconf, 2.64 ATM, wile the version we have is 2.69 so it doesn't work out of the box. This issue to deal with this task.

[dmik]

I tried to re-generate everything with autoconf 2.69 (after hacking config/override.m4 to not abort if it's not 2.64). However, something went wrong and I couldn't manage to get a working configure for the gcc subdirectory (in particular, the regenerated aclocal.m4 was not correct). Perhaps, they fixed the version number because of that. Anyway, we have to either fix it or port autoconf 2.64 specifically for gcc (I don't think it's difficult given that we already have the 2.69 version working).