Remove have_framework() returns false on Yosemite (the $LDFLAGS -framework addition makes this unnecessary anyway, and the have_header() check is a good enough proxy). "gem install" runs "make clean" before running "make", so add generated dispatch/object.h to DISTCLEANFILES instead of CLEANFILES, to fix Yosemite builds (issue #1).
Bump version number from 1.7 to 1.8 (more GCC on Yosemite build fixes)