distribute pkgconfig file

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
do not include /usr/local/include path

This should be done using the COMPILER_PATH environment variable
if needed (in .bashrc), but should not really be needed at all.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
remove libdir hack

This does not work with Debian (which uses lib32 or multiarch) nor
when cross-compiling.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>