fix gcc4x variants in pymol package

[howarth@…]

The change in pymol 1.5 to no longer support 'python setup.py build' but only use
'python setup.py install' to both build and install pymol has broken the previous

infrastructure in the Portfile for building compiler variants of the package. The

attached Portfile.diff...

1) Updates the package to current pymol svn
2) Adds the gcc47 compiler variant
3) Changes the build.env to destroot.env to that the compilers are set from
configure.compiler

Tested on Lion for standard and +gcc45 variant builds.

[howarth@…]

Portfile diff to fix broken compiler variants