Use `?='.

ChangeLog

@@ -9,7 +9,8 @@
 
 	* builds/unix/install.mk (install): Fix path for ftmodule.h.
 
-	* Makefile, *.mk: Use `?=' where appropriate.
+	* Makefile, *.mk, builds/unix/unix-cc.in, builds/unix-def.in: Use
+	`?=' where appropriate.
 
 	* builds/detect.mk (TOP_DIR), builds/os2/os2-dev.mk (TOP_DIR),
 	builds/win32/w32-dev.mk (TOP_DIR): Removed.  Defined elsewhere.

builds/unix/unix-cc.in

@@ -2,7 +2,7 @@
 # FreeType 2 template for Unix-specific compiler definitions
 #
 
-# Copyright 1996-2000, 2002, 2003, 2005 by
+# Copyright 1996-2000, 2002, 2003, 2005, 2006 by
 # David Turner, Robert Wilhelm, and Werner Lemberg.
 #
 # This file is part of the FreeType project, and may only be used, modified,
@@ -15,9 +15,7 @@
 CC           := @CC@
 COMPILER_SEP := $(SEP)
 
-ifndef LIBTOOL
-  LIBTOOL := $(BUILD_DIR)/libtool
-endif
+LIBTOOL ?= $(BUILD_DIR)/libtool
 
 
 # The object file extension (for standard and static libraries).  This can be

builds/unix/unix-def.in

@@ -20,9 +20,7 @@ DELDIR    := @RMDIR@
 SEP       := /
 
 # this is used for `make distclean' and `make install'
-ifndef OBJ_BUILD
-  OBJ_BUILD := $(BUILD_DIR)
-endif
+OBJ_BUILD ?= $(BUILD_DIR)
 
 # don't use `:=' here since the path stuff will be included after this file
 #