configure: if there's no fontconfig, assume no fonts are available

No idea how to check what fonts are installed on Windows/Mac;
only safe thing to do is to disable the tests if --without-fonts.

Change-Id: Ia27d866d9964f7e4e1ebfaba7ee4a7ce53b800b0
diff --git a/configure.ac b/configure.ac
index 6ee677e..1043561 100644
--- a/configure.ac
+++ b/configure.ac
@@ -11150,7 +11150,7 @@ else
            fi
        fi
    else
        TEST_FONTS_MISSING=0
        TEST_FONTS_MISSING=1
    fi
fi
AC_SUBST(WITH_FONTS)