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-prototypes
36EXTRA_WARNINGS += -Wswitch-default
37EXTRA_WARNINGS += -Wswitch-enum
38EXTRA_WARNINGS += -Wundef
39EXTRA_WARNINGS += -Wwrite-strings
40EXTRA_WARNINGS += -Wformat
41
42ifneq ($(CC), clang)
43EXTRA_WARNINGS += -Wstrict-aliasing=3
44endif
45
46ifneq ($(findstring $(MAKEFLAGS), w),w)
47PRINT_DIR = --no-print-directory
48else
49NO_SUBDIR = :
50endif
51
52ifneq ($(filter 4.%,$(MAKE_VERSION)),)  # make-4
53ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
54  silent=1
55endif
56else					# make-3.8x
57ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
58  silent=1
59endif
60endif
61
62#
63# Define a callable command for descending to a new directory
64#
65# Call by doing: $(call descend,directory[,target])
66#
67descend = \
68	+mkdir -p $(OUTPUT)$(1) && \
69	$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
70
71QUIET_SUBDIR0  = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
72QUIET_SUBDIR1  =
73
74ifneq ($(silent),1)
75  ifneq ($(V),1)
76	QUIET_CC       = @echo '  CC       '$@;
77	QUIET_CC_FPIC  = @echo '  CC FPIC  '$@;
78	QUIET_AR       = @echo '  AR       '$@;
79	QUIET_LINK     = @echo '  LINK     '$@;
80	QUIET_MKDIR    = @echo '  MKDIR    '$@;
81	QUIET_GEN      = @echo '  GEN      '$@;
82	QUIET_SUBDIR0  = +@subdir=
83	QUIET_SUBDIR1  = ;$(NO_SUBDIR) \
84			  echo '  SUBDIR   '$$subdir; \
85			 $(MAKE) $(PRINT_DIR) -C $$subdir
86	QUIET_FLEX     = @echo '  FLEX     '$@;
87	QUIET_BISON    = @echo '  BISON    '$@;
88
89	descend = \
90		+@echo	       '  DESCEND  '$(1); \
91		mkdir -p $(OUTPUT)$(1) && \
92		$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
93
94	QUIET_CLEAN    = @printf '  CLEAN    %s\n' $1;
95	QUIET_INSTALL  = @printf '  INSTALL  %s\n' $1;
96  endif
97endif
98