On Linux/MinGW, use the unix doc layout
It would be cool to use the unix doc install layout (prefix/share/...) when cross-compiling from linux to windows using mingw (WIN32 is defined in cmake):
if(WIN32)
set(GL2PS_DOC .)
else(WIN32)
set(GL2PS_DOC share/doc/gl2ps)
endif(WIN32)
Here is a patch: doc.patch