Fix AC_CHECK_FT2.

Only check PATH for freetype-config if we did not already find it from a
prefix option.

builds/unix/freetype2.m4

@@ -1,7 +1,7 @@
 # Configure paths for FreeType2
 # Marcelo Magallon 2001-10-26, based on gtk.m4 by Owen Taylor
 #
-# Copyright 2001, 2003, 2007 by
+# Copyright 2001, 2003, 2007, 2009 by
 # David Turner, Robert Wilhelm, and Werner Lemberg.
 #
 # This file is part of the FreeType project, and may only be used, modified,
@@ -15,7 +15,7 @@
 # generated by Autoconf, under the same distribution terms as the rest of
 # that program.
 #
-# serial 2
+# serial 3
 
 # AC_CHECK_FT2([MINIMUM-VERSION [, ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]])
 # Test for FreeType 2, and define FT2_CFLAGS and FT2_LIBS.
@@ -60,7 +60,9 @@ AC_DEFUN([AC_CHECK_FT2],
      fi
    fi
 
-   AC_PATH_PROG([FT2_CONFIG], [freetype-config], [no])
+   if test "x$FT2_CONFIG" = x ; then
+     AC_PATH_PROG([FT2_CONFIG], [freetype-config], [no])
+   fi
 
    min_ft_version=m4_if([$1], [], [7.0.1], [$1])
    AC_MSG_CHECKING([for FreeType -- version >= $min_ft_version])