1 # ==========================================================================
3 # ==========================================================================
10 # Init all relevant variables used in kbuild files so
11 # 1) they have correct type
12 # 2) they do not inherit any value from the environment
33 # Read auto.conf if it exists, otherwise ignore
34 -include include/config/auto.conf
36 include scripts/Kbuild.include
38 # For backward compatibility check that these variables do not change
39 save-cflags := $(CFLAGS)
41 # The filename Kbuild has precedence over Makefile
42 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
43 kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
44 include $(kbuild-file)
46 # If the save-* variables changed error out
47 ifeq ($(KBUILD_NOPEDANTIC),)
48 ifneq ("$(save-cflags)","$(CFLAGS)")
49 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
53 include scripts/Makefile.lib
56 ifneq ($(hostprogs-y),$(host-progs))
57 $(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
58 hostprogs-y += $(host-progs)
62 # Do not include host rules unless needed
63 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
64 include scripts/Makefile.host
67 ifneq ($(KBUILD_SRC),)
68 # Create output directory if not already present
69 _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
71 # Create directories for object files if directory does not exist
72 # Needed when obj-y := dir/file.o syntax is used
73 _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
77 $(warning kbuild: Makefile.build is included improperly)
80 # ===========================================================================
82 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
83 lib-target := $(obj)/lib.a
84 obj-y += $(obj)/lib-ksyms.o
87 ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
88 builtin-target := $(obj)/built-in.o
91 modorder-target := $(obj)/modules.order
93 # We keep a list of all modules in $(MODVERDIR)
95 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
96 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
97 $(subdir-ym) $(always)
100 # Linus' kernel sanity checking tool
101 ifneq ($(KBUILD_CHECKSRC),0)
102 ifeq ($(KBUILD_CHECKSRC),2)
103 quiet_cmd_force_checksrc = CHECK $<
104 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
106 quiet_cmd_checksrc = CHECK $<
107 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
111 # Do section mismatch analysis for each module/built-in.o
112 ifdef CONFIG_DEBUG_SECTION_MISMATCH
113 cmd_secanalysis = ; scripts/mod/modpost $@
116 # Compile C sources (.c)
117 # ---------------------------------------------------------------------------
119 # Default is built-in, unless we know otherwise
121 $(if $(part-of-module), \
122 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
123 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
124 quiet_modtag := $(empty) $(empty)
126 $(real-objs-m) : part-of-module := y
127 $(real-objs-m:.o=.i) : part-of-module := y
128 $(real-objs-m:.o=.s) : part-of-module := y
129 $(real-objs-m:.o=.lst): part-of-module := y
131 $(real-objs-m) : quiet_modtag := [M]
132 $(real-objs-m:.o=.i) : quiet_modtag := [M]
133 $(real-objs-m:.o=.s) : quiet_modtag := [M]
134 $(real-objs-m:.o=.lst): quiet_modtag := [M]
136 $(obj-m) : quiet_modtag := [M]
138 # Default for not multi-part modules
139 modname = $(basetarget)
141 $(multi-objs-m) : modname = $(modname-multi)
142 $(multi-objs-m:.o=.i) : modname = $(modname-multi)
143 $(multi-objs-m:.o=.s) : modname = $(modname-multi)
144 $(multi-objs-m:.o=.lst) : modname = $(modname-multi)
145 $(multi-objs-y) : modname = $(modname-multi)
146 $(multi-objs-y:.o=.i) : modname = $(modname-multi)
147 $(multi-objs-y:.o=.s) : modname = $(modname-multi)
148 $(multi-objs-y:.o=.lst) : modname = $(modname-multi)
150 quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
151 cmd_cc_s_c = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
153 $(obj)/%.s: $(src)/%.c FORCE
154 $(call if_changed_dep,cc_s_c)
156 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
157 cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
159 $(obj)/%.i: $(src)/%.c FORCE
160 $(call if_changed_dep,cpp_i_c)
162 # These mirror gensymtypes_S and co below, keep them in synch.
163 cmd_gensymtypes_c = \
164 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
165 $(GENKSYMS) $(if $(1), -T $(2)) \
166 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
167 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
168 $(if $(KBUILD_PRESERVE),-p) \
169 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
171 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
172 cmd_cc_symtypes_c = \
174 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
175 test -s $@ || rm -f $@
177 $(obj)/%.symtypes : $(src)/%.c FORCE
178 $(call cmd,cc_symtypes_c)
181 # Generate .ll files from .c
182 quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
183 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
185 $(obj)/%.ll: $(src)/%.c FORCE
186 $(call if_changed_dep,cc_ll_c)
189 # The C file is compiled and updated dependency information is generated.
190 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
192 quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
194 ifndef CONFIG_MODVERSIONS
195 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
198 # When module versioning is enabled the following steps are executed:
199 # o compile a .tmp_<file>.o from <file>.c
200 # o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
201 # not export symbols, we just rename .tmp_<file>.o to <file>.o and
203 # o otherwise, we calculate symbol versions using the good old
204 # genksyms on the preprocessed source and postprocess them in a way
205 # that they are usable as a linker script
206 # o generate <file>.o from .tmp_<file>.o using the linker to
207 # replace the unresolved symbols __crc_exported_symbol with
208 # the actual value of the checksum generated by genksyms
210 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
212 cmd_modversions_c = \
213 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
214 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
215 > $(@D)/.tmp_$(@F:.o=.ver); \
217 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
218 -T $(@D)/.tmp_$(@F:.o=.ver); \
219 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
221 mv -f $(@D)/.tmp_$(@F) $@; \
225 ifdef CONFIG_FTRACE_MCOUNT_RECORD
226 ifdef BUILD_C_RECORDMCOUNT
227 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
228 RECORDMCOUNT_FLAGS = -w
230 # Due to recursion, we must skip empty.o.
231 # The empty.o file is created in the make process in order to determine
232 # the target endianness and word size. It is made before all other C
233 # files, including recordmcount.
234 sub_cmd_record_mcount = \
235 if [ $(@) != "scripts/mod/empty.o" ]; then \
236 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
238 recordmcount_source := $(srctree)/scripts/recordmcount.c \
239 $(srctree)/scripts/recordmcount.h
241 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
242 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
243 "$(if $(CONFIG_64BIT),64,32)" \
244 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
245 "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
246 "$(if $(part-of-module),1,0)" "$(@)";
247 recordmcount_source := $(srctree)/scripts/recordmcount.pl
248 endif # BUILD_C_RECORDMCOUNT
249 cmd_record_mcount = \
250 if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \
251 "$(CC_FLAGS_FTRACE)" ]; then \
252 $(sub_cmd_record_mcount) \
254 endif # CONFIG_FTRACE_MCOUNT_RECORD
256 ifdef CONFIG_STACK_VALIDATION
257 ifneq ($(SKIP_STACK_VALIDATION),1)
259 __objtool_obj := $(objtree)/tools/objtool/objtool
261 objtool_args = $(if $(CONFIG_ORC_UNWINDER),orc generate,check)
263 ifndef CONFIG_FRAME_POINTER
264 objtool_args += --no-fp
266 ifdef CONFIG_GCOV_KERNEL
267 objtool_args += --no-unreachable
270 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
271 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
272 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
273 cmd_objtool = $(if $(patsubst y%,, \
274 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
275 $(__objtool_obj) $(objtool_args) "$(@)";)
276 objtool_obj = $(if $(patsubst y%,, \
277 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
280 endif # SKIP_STACK_VALIDATION
281 endif # CONFIG_STACK_VALIDATION
283 # Rebuild all objects when objtool changes, or is enabled/disabled.
284 objtool_dep = $(objtool_obj) \
285 $(wildcard include/config/orc/unwinder.h \
286 include/config/stack/validation.h)
289 $(call echo-cmd,checksrc) $(cmd_checksrc) \
290 $(call cmd_and_fixdep,cc_o_c) \
291 $(cmd_modversions_c) \
292 $(call echo-cmd,objtool) $(cmd_objtool) \
293 $(call echo-cmd,record_mcount) $(cmd_record_mcount)
297 $(call cmd_and_fixdep,as_o_S) \
298 $(cmd_modversions_S) \
299 $(call echo-cmd,objtool) $(cmd_objtool)
302 # List module undefined symbols (or empty line if not enabled)
303 ifdef CONFIG_TRIM_UNUSED_KSYMS
304 cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
306 cmd_undef_syms = echo
309 # Built-in and composite module parts
310 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
311 $(call cmd,force_checksrc)
312 $(call if_changed_rule,cc_o_c)
314 # Single-part modules are special since we need to mark them in $(MODVERDIR)
316 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
317 $(call cmd,force_checksrc)
318 $(call if_changed_rule,cc_o_c)
319 @{ echo $(@:.o=.ko); echo $@; \
320 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
322 quiet_cmd_cc_lst_c = MKLST $@
323 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
324 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
325 System.map $(OBJDUMP) > $@
327 $(obj)/%.lst: $(src)/%.c FORCE
328 $(call if_changed_dep,cc_lst_c)
330 # Compile assembler sources (.S)
331 # ---------------------------------------------------------------------------
333 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
335 $(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
336 $(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
338 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
339 # or a file that it includes, in order to get versioned symbols. We build a
340 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
341 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
343 # This is convoluted. The .S file must first be preprocessed to run guards and
344 # expand names, then the resulting exports must be constructed into plain
345 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
346 # to make the genksyms input.
348 # These mirror gensymtypes_c and co above, keep them in synch.
349 cmd_gensymtypes_S = \
350 (echo "\#include <linux/kernel.h>" ; \
351 echo "\#include <asm/asm-prototypes.h>" ; \
352 $(CPP) $(a_flags) $< | \
353 grep "\<___EXPORT_SYMBOL\>" | \
354 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
355 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
356 $(GENKSYMS) $(if $(1), -T $(2)) \
357 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
358 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
359 $(if $(KBUILD_PRESERVE),-p) \
360 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
362 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
363 cmd_cc_symtypes_S = \
365 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
366 test -s $@ || rm -f $@
368 $(obj)/%.symtypes : $(src)/%.S FORCE
369 $(call cmd,cc_symtypes_S)
372 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
373 cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
375 $(obj)/%.s: $(src)/%.S FORCE
376 $(call if_changed_dep,cpp_s_S)
378 quiet_cmd_as_o_S = AS $(quiet_modtag) $@
380 ifndef CONFIG_MODVERSIONS
381 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
385 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
387 ifeq ($(ASM_PROTOTYPES),)
388 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
392 # versioning matches the C process described above, with difference that
393 # we parse asm-prototypes.h C header to get function definitions.
395 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
397 cmd_modversions_S = \
398 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
399 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
400 > $(@D)/.tmp_$(@F:.o=.ver); \
402 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
403 -T $(@D)/.tmp_$(@F:.o=.ver); \
404 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
406 mv -f $(@D)/.tmp_$(@F) $@; \
411 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
412 $(call if_changed_rule,as_o_S)
414 targets += $(real-objs-y) $(real-objs-m) $(lib-y)
415 targets += $(extra-y) $(MAKECMDGOALS) $(always)
417 # Linker scripts preprocessor (.lds.S -> .lds)
418 # ---------------------------------------------------------------------------
419 quiet_cmd_cpp_lds_S = LDS $@
420 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
421 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
423 $(obj)/%.lds: $(src)/%.lds.S FORCE
424 $(call if_changed_dep,cpp_lds_S)
427 # ---------------------------------------------------------------------------
428 quiet_cmd_asn1_compiler = ASN.1 $@
429 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
430 $(subst .h,.c,$@) $(subst .c,.h,$@)
432 .PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
434 $(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
435 $(call cmd,asn1_compiler)
437 # Build the compiled-in targets
438 # ---------------------------------------------------------------------------
440 # To build objects in subdirs, we need to descend into the directories
441 $(sort $(subdir-obj-y)): $(subdir-ym) ;
444 # Rule to compile a set of .o files into one .o file
448 ifdef CONFIG_THIN_ARCHIVES
449 cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
450 cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
451 quiet_cmd_link_o_target = AR $@
453 cmd_make_builtin = $(LD) $(ld_flags) -r -o
454 cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
455 quiet_cmd_link_o_target = LD $@
458 # If the list of objects to link is empty, just create an empty built-in.o
459 cmd_link_o_target = $(if $(strip $(obj-y)),\
460 $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
462 $(cmd_make_empty_builtin) $@)
464 $(builtin-target): $(obj-y) FORCE
465 $(call if_changed,link_o_target)
467 targets += $(builtin-target)
468 endif # builtin-target
471 # Rule to create modules.order file
473 # Create commands to either record .ko file or cat modules.order from
476 $(foreach m, $(modorder), \
477 $(if $(filter %/modules.order, $m), \
478 cat $m;, echo kernel/$m;))
480 $(modorder-target): $(subdir-ym) FORCE
481 $(Q)(cat /dev/null; $(modorder-cmds)) > $@
484 # Rule to compile a set of .o files into one .a file
487 quiet_cmd_link_l_target = AR $@
489 ifdef CONFIG_THIN_ARCHIVES
490 cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
492 cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
495 $(lib-target): $(lib-y) FORCE
496 $(call if_changed,link_l_target)
498 targets += $(lib-target)
500 dummy-object = $(obj)/.lib_exports.o
501 ksyms-lds = $(dot-target).lds
502 ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
503 ref_prefix = EXTERN(_
508 quiet_cmd_export_list = EXPORTS $@
509 cmd_export_list = $(OBJDUMP) -h $< | \
510 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
511 rm -f $(dummy-object);\
512 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
513 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
514 rm $(dummy-object) $(ksyms-lds)
516 $(obj)/lib-ksyms.o: $(lib-target) FORCE
517 $(call if_changed,export_list)
519 targets += $(obj)/lib-ksyms.o
524 # Rule to link composite objects
526 # Composite objects are specified in kbuild makefile as follows:
527 # <composite-object>-objs := <list of .o files>
529 # <composite-object>-y := <list of .o files>
531 # <composite-object>-m := <list of .o files>
532 # The -m syntax only works if <composite object> is a module
534 $(filter $(addprefix $(obj)/, \
535 $($(subst $(obj)/,,$(@:.o=-objs))) \
536 $($(subst $(obj)/,,$(@:.o=-y))) \
537 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
539 cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
541 ifdef CONFIG_THIN_ARCHIVES
542 quiet_cmd_link_multi-y = AR $@
543 cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
545 quiet_cmd_link_multi-y = LD $@
546 cmd_link_multi-y = $(cmd_link_multi-link)
549 quiet_cmd_link_multi-m = LD [M] $@
550 cmd_link_multi-m = $(cmd_link_multi-link)
552 $(multi-used-y): FORCE
553 $(call if_changed,link_multi-y)
554 $(call multi_depend, $(multi-used-y), .o, -objs -y)
556 $(multi-used-m): FORCE
557 $(call if_changed,link_multi-m)
558 @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
559 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
560 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
562 targets += $(multi-used-y) $(multi-used-m)
566 # ---------------------------------------------------------------------------
568 PHONY += $(subdir-ym)
570 $(Q)$(MAKE) $(build)=$@
572 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
573 # ---------------------------------------------------------------------------
579 # Read all saved command lines and dependencies for the $(targets) we
580 # may be building above, using $(if_changed{,_dep}). As an
581 # optimization, we don't need to read them if the target does not
582 # exist, we will rebuild anyway in that case.
584 targets := $(wildcard $(sort $(targets)))
585 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
587 ifneq ($(cmd_files),)
591 # Declare the contents of the .PHONY variable as phony. We keep that
592 # information in a variable se we can use it in if_changed and friends.