This looks like a recurring and somewhat sore topic.

For those of us that have been fighting the dreaded:

./Include/pyport.h:730:2: error: #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."

when performing a 64 bit compile. I believe I have identified the problems. All of which are directly related to the Makefile(s) that are generated as part of the configure script. There does not seem to be anything wrong with the configure script or anything else once all of the Makefiles are corrected Python will build 64 bit

Although it is possible to pass the following environment variables to configure as is typical on most open source software:

  CC          C compiler command
  CFLAGS      C compiler flags
  LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
              nonstandard directory <lib dir>
  CPPFLAGS    C/C++ preprocessor flags, e.g. -I<include dir> if you have
              headers in a nonstandard directory <include dir>
  CPP         C preprocessor

These flags are *not* being processed through to the generated Makefiles. This is where the problem is. configure is doing everything right and generating all of the necessary stuff for a 64 bit compile but when the compile is actually performed - the necessary CFLAGS are missing and a 32 bit compile is initiated.

Taking a close look at the first failure I found the following:

gcc -pthread -c -fno-strict-aliasing -DNDEBUG -g -O3 -Wall -Wstrict-prototypes  -I. -I./Include  -fPIC -DPy_BUILD_CORE -o Modules/python.o ./Modules/python.c

Where are my CFLAGS???

I ran the configure with:

CFLAGS="-O3 -m64 -mcpu=ultrasparc -L/opt/lib/sparcv9 -R/opt/lib/sparcv9" \
CXXFLAGS="-O3 -m64 -mcpu=ultrasparc -L/opt/lib/sparcv9 -R/opt/lib/sparcv9" \
LDFLAGS="-m64 -L/opt/lib/sparcv9 -R/opt/lib/sparcv9" \
./configure --prefix=/opt \
--enable-shared \
--libdir=/opt/lib/sparcv9

Checking the config.log and config.status it was clear that the flags were used properly as the configure script ran however, the failure is in the various Makefiles to actually reference the CFLAGS and LDFLAGS.

LDFLAGS is simply not included in any of the link stages in the Makefiles and CFLAGS is overidden by BASECFLAGS, OPT and EXTRA_CFLAGS!

Ah!

EXTRA_CFLAGS="-O3 -m64 -mcpu=ultrasparc -L/opt/lib/sparcv9 -R/opt/lib/sparcv9" \
make

Actually got the core parts to compile for the library and then failed to build the library because - LDFLAGS was missing from the Makefile for the library link stage - :-(

Close examination suggests that the OPT environment variable could be used to pass the necessary flags through from conifgure but this still did not help the link stage problems.

The fixes are pretty minimal to ensure that the configure variables are passed into the Makefile. My patch to the Makefile.pre.in is attached to this bug report.

Once these changes are made Python will build properly for both 32 and 64 bit platforms with the correct CFLAGS and LDFLAGS passed into the configure script.

BTW, while this bug is reported under a Solaris/gcc build the patches to Makefile.pre.in should fix similar build issues on all platforms.