for host compiler.

Patch by Jakub Wilk.

Patch by Jakub Wilk.

python executable

The __os_install_macro defines some post-processing activities during an rpm
build; one of the scripts it calls is brp-python-bytecompile, which can take
an argument: the python executable with which to byte-compile .py files in the
package payload.

In some older versions of rpm (e.g. in RHEL 6), this invocation doesn't pass
in an argument, and brp-python-bytecompile defaults to using /usr/bin/python,
which can lead to the .py files being byte-compiled for the wrong version of
python.  This has been fixed in later versions of rpm by passing in
%{__python} as an argument to brp-python-bytecompile.

Workaround this by detecting if __os_install_post has a 0-argument invocation
of brp-python-bytecompile, and if so generating an equivalent macro that has
the argument, and explicitly provide the new definition within the specfile.

python executable

The __os_install_macro defines some post-processing activities during an rpm
build; one of the scripts it calls is brp-python-bytecompile, which can take
an argument: the python executable with which to byte-compile .py files in the
package payload.

In some older versions of rpm (e.g. in RHEL 6), this invocation doesn't pass
in an argument, and brp-python-bytecompile defaults to using /usr/bin/python,
which can lead to the .py files being byte-compiled for the wrong version of
python.  This has been fixed in later versions of rpm by passing in
%{__python} as an argument to brp-python-bytecompile.

Workaround this by detecting if __os_install_post has a 0-argument invocation
of brp-python-bytecompile, and if so generating an equivalent macro that has
the argument, and explicitly provide the new definition within the specfile.

- Try to avoid building Python or extension modules with problematic
  llvm-gcc compiler.
- Since Xcode 4 removes ppc support, extension module builds now
  check for ppc compiler support and automatically remove ppc and
  ppc64 archs when not available.
- Since Xcode 4 no longer install SDKs in default locations,
  extension module builds now revert to using installed headers
  and libs if the SDK used to build the interpreter is not
  available.
- Update ./configure to use better defaults for universal builds;
  in particular, --enable-universalsdk=yes uses the Xcode default
  SDK and --with-universal-archs now defaults to "intel" if ppc
  not available.

Patch by Ralf Schmitt.

These regex changes fix a number of issues for distutils on Windows:
- #6884: impossible to include a file starting with 'build'
- #9691 and #14004: sdist includes too many files
- #13193: test_filelist failures

This commit replaces the incorrect changes done in 0a94e2f807c7 and
90b30d62caf2 to fix #13193; we were too eager to fix the test failures
and I did not study the code enough before greenlighting patches.  This
time we have unit tests from the problems reported by users to be sure
we have the right fix.

Thanks to Nadeem Vawda for his help.