makefile sample to rebuild on flags change

.gitignore

*~
*.bak
*.orig
\#*\#

.build/
sh.exe

a

b

c

d

e

f

makefile

FLAGS ?= 0

SHELL ?= sh

all: .build/all

.build/all: .build/a .build/b .build/c .build/d .build/e .build/f
	touch .build/all

.build/: FORCE
	mkdir -p $@

.build/.flags: .build/ FORCE
	echo "FLAGS=${FLAGS}" >[email protected]; \
	if ! cmp -s [email protected] $@; then mv -f [email protected] $@; fi; \
	rm -fr [email protected]

.build/a: a .build/.flags
	touch $@

.build/b: b .build/.flags
	touch $@

.build/c: c .build/.flags
	touch $@

.build/d: d .build/.flags
	touch $@

.build/e: e .build/.flags
	touch $@

.build/f: f .build/.flags
	touch $@

.PHONY: FORCE
FORCE: ;

.PHONY: clean
clean:
	rm -fr .build