audio/komposter: prepare for freetype2 upgrade

- freetype2 will no longer ship freetype-config (which was a pkg-config
wrapper) in the near future -- use pkg-config to gather the required
flags.

PR:		251512

audio/komposter/files/patch-acinclude.m4

@@ -0,0 +1,14 @@
+--- acinclude.m4.orig	2021-08-07 13:54:37 UTC
++++ acinclude.m4
+@@ -601,10 +601,7 @@ dnl Incorporate Freetype2.
+ dnl AC_INCORPORATE_FREETYPE2([version], [define on found], [obligatory])
+ AC_DEFUN([AC_INCORPORATE_FREETYPE2],
+ [
+-	AC_CHECK_FT2([$1],
+-		freetype2=[yes],
+-		freetype2=[no])
+-	AC_INCORPORATE([Freetype2], [$freetype2], [$FT2_CFLAGS], [$FT2_LIBS], [$2], [$3])
++	AC_INCORPORATE_PKGCONFIG([freetype2],[$1],[$2],[no])
+ ])
+ 
+ dnl Incorporate GLEW.