%general-entities; ]> GMP CC="gcc -isystem /usr/include ${BUILD64}" CXX="g++ -isystem /usr/include ${BUILD64}" \ LDFLAGS="-Wl,-rpath-link,/lib64 ${BUILD64}" ./configure --prefix=/usr \ --libdir=/usr/lib64 --enable-cxx --enable-mpbsd Create the 64bit header file: mv -v /usr/include/gmp{,-64}.h Finally, Create a stub header in the place of the originals: cat > /usr/include/gmp.h << "EOF" /* gmp.h - Stub Header */ #ifndef __STUB__GMP_H__ #define __STUB__GMP_H__ #if defined(__x86_64__) || \ defined(__sparc64__) || \ defined(__arch64__) || \ defined(__powerpc64__) || \ defined (__s390x__) # include "gmp-64.h" #else # include "gmp-32.h" #endif #endif /* __STUB__GMP_H__ */ EOF