allow passing BUILD_DIR to convenience makefile as an argument incase you dont...

allow passing BUILD_DIR to convenience makefile as an argument incase you dont want to build in the default path.

GNUmakefile

@@ -34,10 +34,13 @@ OS_NCASE:=$(shell uname -s | tr '[A-Z]' '[a-z]')
 
 # Source and Build DIR's
 BLENDER_DIR:=$(shell pwd -P)
-BUILD_DIR:=$(shell dirname $(BLENDER_DIR))/build/$(OS_NCASE)
 BUILD_TYPE:=Release
 BUILD_CMAKE_ARGS:=
 
+ifndef BUILD_DIR
+	BUILD_DIR:=$(shell dirname $(BLENDER_DIR))/build/$(OS_NCASE)
+endif
+
 
 # -----------------------------------------------------------------------------
 # additional targets for the build configuration
@@ -120,6 +123,9 @@ help:
 	@echo "  * headless  - build without an interface (renderfarm or server automation)"
 	@echo "  * bpy       - build as a python module which can be loaded from python directly"
 	@echo ""
+	@echo "  Note, passing the argument 'BUILD_DIR=path' when calling make will override the default build dir."
+	@echo ""
+	@echo ""
 	@echo "Project Files for IDE's"
 	@echo "  * project_qtcreator - QtCreator Project Files"
 	@echo "  * project_netbeans  - NetBeans Project Files"
@@ -130,9 +136,8 @@ help:
 	@echo "  * package_pacman  - build an arch linux pacmanpackage"
 	@echo "  * package_archive - build an archive package"
 	@echo ""
-	@echo "Other Targets"
+	@echo "Other Targets (not assosiated with building blender)"
 	@echo "  * translations  - update blenders translation files in po/"
-	# TODO, doxygen and sphinx docs
 	@echo ""
 	@echo "Testing Targets (not assosiated with building blender)"
 	@echo "  * test            - run ctest, currently tests import/export, operator execution and that python modules load"
@@ -145,7 +150,7 @@ help:
 	@echo "  * check_splint    - run blenders source through splint (C only)"
 	@echo "  * check_sparse    - run blenders source through sparse (C only)"
 	@echo ""
-	@echo "Documentation Targets"
+	@echo "Documentation Targets (not assosiated with building blender)"
 	@echo "  * doc_py   - generate sphinx python api docs"
 	@echo "  * doc_dna  - generate blender file format reference"
 	@echo "  * doc_man  - generate manpage"