libdbusmenu: require glib-2.0 in pkg-config

libdbusmenu-glib has headers which include <glib.h>, but does not
declare glib as a dependency. This causes include errors if you try to
build with just libdbusmenu-glib.

pkgs/development/libraries/libdbusmenu/default.nix

@@ -27,6 +27,10 @@ stdenv.mkDerivation (finalAttrs: {
       "3" = gtk3;
     }.${gtkVersion} or (throw "unknown GTK version ${gtkVersion}");
 
+  patches = [
+    ./requires-glib.patch
+  ];
+
   postPatch = ''
     for f in {configure,ltmain.sh,m4/libtool.m4}; do
       substituteInPlace $f \

pkgs/development/libraries/libdbusmenu/requires-glib.patch

@@ -0,0 +1,11 @@
+--- a/libdbusmenu-glib/dbusmenu-glib-0.4.pc.in
++++ b/libdbusmenu-glib/dbusmenu-glib-0.4.pc.in
+@@ -5,7 +5,7 @@
+ includedir=@includedir@
+
+ Cflags: -I${includedir}/libdbusmenu-glib-0.4
+-Requires:
++Requires: glib-2.0
+ Libs: -L${libdir} -ldbusmenu-glib
+
+ Name: libdbusmenu-glib