Modify ${CPPFLAGS} to add pg_config's setting for PGINCLUDEDIR to the

include path during compilation.  On FreeBSD at least, postgresql's
include files are installed into /usr/local/include/postgresql

configure.in

@@ -58,6 +58,9 @@ SAVE_CFLAGS="$CFLAGS"
 AC_PROG_CC([$($PG_CONFIG --cc)])
 CFLAGS="$SAVE_CFLAGS"
 
+# Add the Postgres PKGINCLUDEDIR to the include search path
+CPPFLAGS="$CPPFLAGS -I$($PG_CONFIG --pkgincludedir)"
+
 # check for a number of CFLAGS that make development easier
 
 # CITUSAC_PROG_CC_CFLAGS_OPT