My efforts to build gcc 4.9.1 have succeeded. The makefile tweak that
corrected the references to the 4.8.1 version number seem to have fixed
the 4.9.1 build failure.
So, here is a summary of what it takes to build a 4.9.1 gcc:
The building compiler must have no trace of the V4 runtime and Win32 api.
It is insufficient to replace them with the V3 versions; the building
compiler itself must be built without them; The first building compiler
that worked for my gcc 4.9.1 build was was gcc 4.8.3; it was built with
the version 3 runtime and win32 api, installed, and then built again and
installed. I expect that a similar rebuild of 4.8.1 would have worked
just as well, but after I found that 4.8.3 produced better error messages,
I stayed with it.
The MinGW package builder environments that I used for my most recent
4.8.3 and 4.9.1 builds are attached. I have deleted the "pristine source"
tarballs to make them small enough for e-mail.
Note that my 4.9.1 build is done with no patches whatsoever - it truly is
a "pristine source" build. My 4.8.3 build includes the additional patch
to fix the Ada bug caused by use of a 64-bit time_t C type. The patch is
a no-op for a 32-bit time_t type, but I am keeping it in my builds, as it
will make Ada immune to a future return to a 64-bit time_t. A similar
patch will go into my next 4.9.1 build. I have filed a bug report for
this with the upstream gcc project.
I Am now using gcc 4.8.3 as my production compiler suite at work. It has
build two very large Ada packages from the GNAVI Sourceforge project
that I use heavily at work, as well as another one that I wrote to
supplement the first two, and successfully compiles the Ada applications
that I write and maintain. Most of what I do is in Ada, but I did rebuild
and install the gmp, mpfr, and mpc libraries and used them for the build
of my 4.8.3 production compiler.
Since the warning messages in the 4.9.1 build log are so different from
those of the 4.8.3 build, I plan to do much more extensive testing of the
4.9.1 compiler. It does build the gmp, mpfr, and mpc libraries, but that
is all that I have done with 4.9.1 at this point. I used them for my most
recent 4.9.1 build.
A final note: if the gcc-4.8.1-4 currently installed by the installer is
using the V4 libraries, I strongly recommend that it be replaced with a
4.8.1-5 version using the good V3 libraries. I suspect that it was built
with the offending V4 libraries, as it would not build 4.9.1.