1ifneq ($(O),)
2ifeq ($(origin O), command line)
3	dummy := $(if $(shell test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)
4	ABSOLUTE_O := $(shell cd $(O) ; pwd)
5	OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/)
6	COMMAND_O := O=$(ABSOLUTE_O)
7ifeq ($(objtree),)
8	objtree := $(O)
9endif
10endif
11endif
12
13# check that the output directory actually exists
14ifneq ($(OUTPUT),)
15OUTDIR := $(shell cd $(OUTPUT) && /bin/pwd)
16$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
17endif
18
19#
20# Include saner warnings here, which can catch bugs:
21#
22EXTRA_WARNINGS := -Wbad-function-cast
23EXTRA_WARNINGS += -Wdeclaration-after-statement
24EXTRA_WARNINGS += -Wformat-security
25EXTRA_WARNINGS += -Wformat-y2k
26EXTRA_WARNINGS += -Winit-self
27EXTRA_WARNINGS += -Wmissing-declarations
28EXTRA_WARNINGS += -Wmissing-prototypes
29EXTRA_WARNINGS += -Wnested-externs
30EXTRA_WARNINGS += -Wno-system-headers
31EXTRA_WARNINGS += -Wold-style-definition
32EXTRA_WARNINGS += -Wpacked
33EXTRA_WARNINGS += -Wredundant-decls
34EXTRA_WARNINGS += -Wshadow
35EXTRA_WARNINGS += -Wstrict-aliasing=3
36EXTRA_WARNINGS += -Wstrict-prototypes
37EXTRA_WARNINGS += -Wswitch-default
38EXTRA_WARNINGS += -Wswitch-enum
39EXTRA_WARNINGS += -Wundef
40EXTRA_WARNINGS += -Wwrite-strings
41EXTRA_WARNINGS += -Wformat
42
43ifneq ($(findstring $(MAKEFLAGS), w),w)
44PRINT_DIR = --no-print-directory
45else
46NO_SUBDIR = :
47endif
48
49#
50# Define a callable command for descending to a new directory
51#
52# Call by doing: $(call descend,directory[,target])
53#
54descend = \
55	+mkdir -p $(OUTPUT)$(1) && \
56	$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
57
58QUIET_SUBDIR0  = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
59QUIET_SUBDIR1  =
60
61ifneq ($(findstring $(MAKEFLAGS),s),s)
62  ifneq ($(V),1)
63	QUIET_CC       = @echo '  CC       '$@;
64	QUIET_CC_FPIC  = @echo '  CC FPIC  '$@;
65	QUIET_AR       = @echo '  AR       '$@;
66	QUIET_LINK     = @echo '  LINK     '$@;
67	QUIET_MKDIR    = @echo '  MKDIR    '$@;
68	QUIET_GEN      = @echo '  GEN      '$@;
69	QUIET_SUBDIR0  = +@subdir=
70	QUIET_SUBDIR1  = ;$(NO_SUBDIR) \
71			  echo '  SUBDIR   '$$subdir; \
72			 $(MAKE) $(PRINT_DIR) -C $$subdir
73	QUIET_FLEX     = @echo '  FLEX     '$@;
74	QUIET_BISON    = @echo '  BISON    '$@;
75
76	descend = \
77		+@echo	       '  DESCEND  '$(1); \
78		mkdir -p $(OUTPUT)$(1) && \
79		$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
80
81	QUIET_CLEAN    = @printf '  CLEAN    %s\n' $1;
82	QUIET_INSTALL  = @printf '  INSTALL  %s\n' $1;
83  endif
84endif
85