How can I set ccshared=-fPIC while executing ./configure?

Question

I am trying to build Python 2.6 for QGIS on RHEL 5. During the making of QGIS I get the following error:

Linking CXX shared library libqgispython.so
/usr/bin/ld: /usr/local/lib/python2.6/config/libpython2.6.a(abstract.o): relocation R_X86_64_32 against `a local symbol' can not be used when making a shared object; recompile with -fPIC
/usr/local/lib/python2.6/config/libpython2.6.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
make[2]: *** [src/python/libqgispython.so.1.0] Error 1
make[1]: *** [src/python/CMakeFiles/qgispython.dir/all] Error 2
make: *** [all] Error 2

What I figure out from this error is that I need to build Python 2.6 with some flag, -fPIC. OK, so I found it in the configure.in file but it checks several conditions and on the basis of those conditions it assigns -fPIC to the CCSHARED flag.

What I did was that after all conditions were checked I added the following line to deliberately use CCSHARED as -fPIC.

CCSHARED="-fPIC";

But it did not work..

How to specify while configuring that I want to set CCSHARED as -fPIC?

Answer 1

Isn't that CCFLAGS? (Haven't been that side of the world for a while.)

Answer 2

1. Run ./configure --help, possibly piping to grep PIC, to see if there's an option to enable this
2. Try setting the environment variable before running configure, e.g. CCSHARED="-fPIC" ./configure (as a single command, assuming bash)

If neither of those work, you need to read the configure code and understand the conditions it tests for better.

Answer 3

I got it working by adding -fPIC after CC= gcc -pthread, i.e CC= gcc -pthread -fPIC in the Makefile.

Answer 4

Run configure with --enable-shared. Then -fPIC will be included as part of the shared flags.

Answer 5

As noted elsewhere, running configure with --enable-shared should cause -fPIC to be included in the compiler flags. However, you may still see the "could not read symbols" error if you attempt to do a parallel build using, e.g., 'make -j8'. I had this same error on RHEL 5.2 and it only went away when I removed the '-j8' from my make invocation...