Fix ./configure to provide a more sensible default for
MACOSX_DEPLOYMENT_TARGET. Currently the default is the minimum OS X level
that supports the universal arch option, typically 10.4, even when no
universalsdk is selected. This causes various desirable features that
depend on later OS X versions, like libedit readline support, to be
omitted from the build. A more complete solution would take into account
the SDK that is being used and better tailor the universal arch options.
For now, change the existing tests to only apply to build systems of 10.5
and earlier; for 10.6 and later, use the build system version as the
default deployment target if the MACOSX_DEPLOYMENT_TARGET environment
variable is not provided.
- 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.
