The source project of this merge request has been removed.
Detect expat using pkg-config
AX_LIB_EXPAThas a big practical issue: It tries to detect expat by injecting various paths, among which is /usr/lib. This is extremely problematic, as /usr/lib usually contains 32-bit libraries on 64-bit systems and thereby kills linkers such as LLD that reject 32-bit binaries when linking 64-bit binaries.
pkg-configdoes not inject /usr/lib, and can also be overridden at configure time.