Add FreeType-dependent functions to fontconfig.def file. (bug 15415)

With PUBLIC_FILES no longer containing the freetype-dependent symbols, those
must be added to the fontconfig.def file build process.
diff --git a/src/Makefile.am b/src/Makefile.am
index 129d74b..b91d0e2 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -142,10 +142,10 @@
 
 CLEANFILES = $(ALIAS_FILES)
 
-fontconfig.def: $(PUBLIC_FILES)
+fontconfig.def: $(PUBLIC_FILES) $(PUBLIC_FT_FILES)
 	echo Generating $@
 	(echo EXPORTS; \
-	(cat $(PUBLIC_FILES) || echo 'FcERROR ()' ) | \
+	(cat $(PUBLIC_FILES) $(PUBLIC_FT_FILES) || echo 'FcERROR ()' ) | \
  	grep '^Fc[^ ]* *(' | sed -e 's/ *(.*$$//' -e 's/^/	/' | \
 	sort; \
 	echo LIBRARY libfontconfig-@LT_CURRENT_MINUS_AGE@.dll; \