I wanted to build a Python extension module written in C99, but Solaris's headers ("sys/feature_test.h") declare that you can't have an XPG 4.2 application using C99.

Investigating led me eventually to Solaris hacker John Levon, who kindly pointed out to me that in the Sun-maintained port of Python, they use a perl script to strip out _XOPEN_SOURCE, _XOPEN_SOURCE_EXTENDED, and _POSIX_SOURCE from pyconfig.h:

http://src.opensolaris.org/source/xref/jds/spec-files/trunk/SUNWPython.spec

(See lines 123-125.)

The attached patch accomplishes the same goal more cleanly by changing the contents of configure.in.  With this patch, I can now build python trunk and release25-maint and also build a C99 extension module:

http://cheeseshop.python.org/pypi/zfec

This patch might also impact "[ 1306253 ] Python 2.4.2c1 fails to build on 64-bit Solaris 10":

https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1306253&group_id=5470

I think perhaps this patch should supercede the patch mentioned in "[ 1116722 ] Solaris 10 fails to compile complexobject.c [FIX incl.]":

https://sourceforge.net/tracker/?func=detail&atid=305470&aid=1116722&group_id=5470