I've built Python 2.6.1 and Python 2.6.2 on x86_64-sun-solaris2.10 using
the Sun Workshop Express (200903) toolchain.  I'm building in 64 bit mode.

Most stuff builds just fine (even warnings are rare), but pyexpat fails
to link with this error:

building 'pyexpat' extension
creating
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/expat
cc -xtarget=native -m64 -xarch=native -KPIC -DNDEBUG -Xa -xO4 -xstrconst
-mt -xtarget=native -m64 -xarch=native -I/local/include
-I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include -DHAVE_EXPAT_CONFIG_H=1 -DUSE_PYEXPAT_CAPI
-I/local/src/RPM/BUILD/Python-2.6.2/./Modules/expat -I.
-I/local/src/RPM/BUILD/Python-2.6.2/./Include -I. -IInclude -I./Include
-I/local/include -I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include -I/usr/local/include
-I/local/src/RPM/BUILD/Python-2.6.2/Include
-I/local/src/RPM/BUILD/Python-2.6.2 -c
/local/src/RPM/BUILD/Python-2.6.2/Modules/pyexpat.c -o
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/pyexpat.o
"/local/src/RPM/BUILD/Python-2.6.2/Modules/pyexpat.c", line 1574:
warning: assignment type mismatch:
    pointer to void "=" pointer to function(pointer to void, pointer to
const ch
ar, int) returning void
cc -xtarget=native -m64 -xarch=native -KPIC -DNDEBUG -Xa -xO4 -xstrconst
-mt -xtarget=native -m64 -xarch=native -I/local/include
-I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include -DHAVE_EXPAT_CONFIG_H=1 -DUSE_PYEXPAT_CAPI
-I/local/src/RPM/BUILD/Python-2.6.2/./Modules/expat -I.
-I/local/src/RPM/BUILD/Python-2.6.2/./Include -I. -IInclude -I./Include
-I/local/include -I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include -I/usr/local/include
-I/local/src/RPM/BUILD/Python-2.6.2/Include
-I/local/src/RPM/BUILD/Python-2.6.2 -c
/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmlparse.c -o
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmlparse.o
cc -xtarget=native -m64 -xarch=native -KPIC -DNDEBUG -Xa -xO4 -xstrconst
-mt -xtarget=native -m64 -xarch=native -I/local/include
-I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include -DHAVE_EXPAT_CONFIG_H=1 -DUSE_PYEXPAT_CAPI
-I/local/src/RPM/BUILD/Python-2.6.2/./Modules/expat -I.
-I/local/src/RPM/BUILD/Python-2.6.2/./Include -I. -IInclude -I./Include
-I/local/include -I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include -I/usr/local/include
-I/local/src/RPM/BUILD/Python-2.6.2/Include
-I/local/src/RPM/BUILD/Python-2.6.2 -c
/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmlrole.c -o
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmlrole.o
cc -xtarget=native -m64 -xarch=native -KPIC -DNDEBUG -Xa -xO4 -xstrconst
-mt -xtarget=native -m64 -xarch=native -I/local/include
-I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include -DHAVE_EXPAT_CONFIG_H=1 -DUSE_PYEXPAT_CAPI
-I/local/src/RPM/BUILD/Python-2.6.2/./Modules/expat -I.
-I/local/src/RPM/BUILD/Python-2.6.2/./Include -I. -IInclude -I./Include
-I/local/include -I/local/
gnu/include -I/local/BerkeleyDB/include -I/local/openssl/include
-I/usr/local/include -I/local/src/RPM/BUILD/Python-2.6.2/Include
-I/local/src/RPM/BUILD/Python-2.6.2 -c
/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmltok.c -o
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmltok.o
cc -xtarget=native -m64 -xarch=native -G -L/local/lib/64
-L/local/gnu/lib/64 -L/local/BerkeleyDB/lib/64 -L/local/openssl/lib/64
-L/local/lib/64 -L/local/gnu/lib/64 -L/local/BerkeleyDB/lib/64
-L/local/openssl/lib/64 -DNDEBUG -Xa -xO4 -xstrconst -mt -xtarget=native
-m64 -xarch=native -I/local/include -I/local/gnu/include
-I/local/BerkeleyDB/include -I/local/openssl/include -I. -IInclude
-I./Include 
-I/local/include -I/local/gnu/include -I/local/BerkeleyDB/include
-I/local/openssl/include
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/pyexpat.o
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmlparse.o
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmlrole.o
build/temp.solaris-2.10-i86pc-2.6/local/src/RPM/BUILD/Python-2.6.2/Modules/expat/xmltok.o
-L/local/lib -L/local/lib/64 -L/local/gnu/lib/64
-L/local/BerkeleyDB/lib/64 -L/local/openssl/lib/64 -L/usr/local/lib -o
build/lib.solaris-2.10-i86pc-2.6/pyexpat.so
*** WARNING: renaming "pyexpat" since importing it failed: ld.so.1:
python: fatal: relocation error: file
build/lib.solaris-2.10-i86pc-2.6/pyexpat.so: symbol
XML_SetCharacterDataHandler: referenced symbol not found

I never tried any of the 2.5.x Python builds, but I can tell you that I
built several versions in the 2.4.x series, and none of those versions
had problems compiling or linking pyexpat.

I do have expat 2.0.1 (also built with the Sun compiler in 64 bit mode)
installed on the system, but from the comments in setup.py and the
compiler output, it appears clear that the expat components that ship
with Python 2.6.x are the ones that are being compiled and attempted for
use in the link.

Please let me know if I can provide any relevant information.

Thanks,

Tim (the Enchanter)