Add real checks for autoconf 2.52 and libtool 1.4 so that we can produce "nice" errors if they are not present.
Add real checks for autoconf 2.52 and libtool 1.4 so that we can
produce "nice" errors if they are not present.

PKRoma/expat,PKRoma/expat,PKRoma/expat,PKRoma/expat