* Makefile, *.mk: 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.
diff --git a/Makefile b/Makefile
index ab8dba5..c1fa16c 100644
--- a/Makefile
+++ b/Makefile
@@ -15,22 +15,18 @@
# Project names
#
-PROJECT := freetype
+PROJECT := freetype
PROJECT_TITLE := FreeType
# The variable TOP_DIR holds the path to the topmost directory in the project
# engine source hierarchy. If it is not defined, default it to `.'.
#
-ifndef TOP_DIR
- TOP_DIR := .
-endif
+TOP_DIR ?= .
# The variable OBJ_DIR gives the location where object files and the
# FreeType library are built.
#
-ifndef OBJ_DIR
- OBJ_DIR := $(TOP_DIR)/objs
-endif
+OBJ_DIR ?= $(TOP_DIR)/objs
include $(TOP_DIR)/builds/toplevel.mk