Use glib 2.

--- pmidi-1.7.1/configure.in	2016-08-09 14:30:40.000000000 +0100
+++ pmidi-1.7.1/configure.in	2025-07-14 13:42:03.232952690 +0100
@@ -60,23 +60,13 @@
 	[included_glib="$withval"],
 	[included_glib=auto])
 
-
-	dnl
-	dnl Check the system header files for glib.h
-	dnl and set the parameters accordingly.
-	dnl
-	if test "$included_glib" = "auto" || test "$included_glib" = "no"; then
-		AC_PATH_PROGS(GLIBCNF, glib-config)
-		if test x"$GLIBCNF" != x""; then
-			CFLAGS="$CFLAGS `$GLIBCNF --cflags`"
-			CPPFLAGS="$CFLAGS `$GLIBCNF --cflags`"
-			LIBS="$LIBS `$GLIBCNF --libs`"
-			WITH_INCLUDED_GLIB=0
-			AC_SUBST(GLIBCNF)
-		fi
-	fi
-
-	AC_CHECK_HEADER(glib.h, WITH_INCLUDED_GLIB=0, WITH_INCLUDED_GLIB=1)
+	PKG_CHECK_MODULES([GLIB], [glib-2.0], [
+		CFLAGS="$GLIB_CFLAGS $CFLAGS"
+		LIBS="$GLIB_LIBS $LIBS"
+		WITH_INCLUDED_GLIB=0
+	], [
+		WITH_INCLUDED_GLIB=1
+	])
 
 	dnl
 	dnl If using the system's GLIB library, setup