configure: express dependency of fontconfig on freetype more clearly

use a "use" entry instead of including the transitive dep into the list
of libraries.
this also removes the redundant check of freetype features from the
fontconfig test code.

Change-Id: I86b78028255c9bf0a62be5ec0f97a62ef3fda36f
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/gui/configure.json

@@ -164,25 +164,20 @@
             "label": "Fontconfig",
             "test": {
                 "head": [
-                    "#include <ft2build.h>",
-                    "#include FT_FREETYPE_H",
                     "#include <fontconfig/fontconfig.h>",
                     "#ifndef FC_RGBA_UNKNOWN",
                     "#  error This version of fontconfig is tool old, it is missing the FC_RGBA_UNKNOWN define",
-                    "#endif",
-                    "#if ((FREETYPE_MAJOR*10000 + FREETYPE_MINOR*100 + FREETYPE_PATCH) < 20110)",
-                    "#  error This version of freetype is too old.",
                     "#endif"
                 ],
                 "main": [
-                    "FT_Face face = 0;",
                     "FcPattern *pattern = 0;"
                 ]
             },
             "sources": [
-                { "type": "pkgConfig", "args": "fontconfig freetype2" },
-                { "type": "freetype", "libs": "-lfontconfig -lfreetype" }
-            ]
+                { "type": "pkgConfig", "args": "fontconfig" },
+                { "type": "freetype", "libs": "-lfontconfig" }
+            ],
+            "use": "freetype"
         },
         "gbm": {
             "label": "GBM",