The update to libexpat 2.7.2 changed various '#define' to '#  define',
which the regexes in generate_pkgconfig.sh don't expect, so that
/usr/lib/pkgconfig/expat.pc ends up containing

Version: ..

rather than

Version: 2.7.2

This breaks in particular the build of graphics/rawtherapee:

--   Package dependency requirement 'expat >= 2.1' could not be satisfied.
Package 'expat' has version '..', required version is '>= 2.1'

Index: generate_pkgconfig.sh
===================================================================
RCS file: /cvs/src/lib/libexpat/generate_pkgconfig.sh,v
diff -u -p -r1.2 generate_pkgconfig.sh
--- generate_pkgconfig.sh	7 Jul 2012 08:25:21 -0000	1.2
+++ generate_pkgconfig.sh	22 Sep 2025 03:01:15 -0000
@@ -50,9 +50,9 @@ if [ ! -w "${objdir}" ]; then
 	exit 1
 fi
 
-version_major_re="s/#define[[:blank:]]XML_MAJOR_VERSION[[:blank:]](.*)/\1/p"
-version_minor_re="s/#define[[:blank:]]XML_MINOR_VERSION[[:blank:]](.*)/\1/p"
-version_micro_re="s/#define[[:blank:]]XML_MICRO_VERSION[[:blank:]](.*)/\1/p"
+version_major_re="s/#[[:blank:]]*define[[:blank:]]XML_MAJOR_VERSION[[:blank:]](.*)/\1/p"
+version_minor_re="s/#[[:blank:]]*define[[:blank:]]XML_MINOR_VERSION[[:blank:]](.*)/\1/p"
+version_micro_re="s/#[[:blank:]]*define[[:blank:]]XML_MICRO_VERSION[[:blank:]](.*)/\1/p"
 version_file=${curdir}/lib/expat.h
 lib_version=$(sed -nE ${version_major_re} ${version_file}).$(sed -nE ${version_minor_re} ${version_file}).$(sed -nE ${version_micro_re} ${version_file})