.PHONY: all
all: _all

# disable built-in rules
.SUFFIXES:

# setup some variables
ROOTDIR := $(dir $(lastword $(MAKEFILE_LIST)))
ROOTDIR := $(dir $(ROOTDIR:%../src/=%))../
BUILDDIR := $(ROOTDIR)build
_PROJ := $(abspath $(dir $(firstword $(MAKEFILE_LIST))))
ABSROOT := $(abspath $(ROOTDIR))
_PROJ := $(_PROJ:$(ABSROOT)/%=%)

ifndef CC
CC=gcc
endif

ifndef RANLIB
RANLIB=ranlib
endif

ifndef LDO
LDO=$(CC)
endif

ifndef CFLAGS
CFLAGS = -MMD -O2 -Wall -g
endif

ifneq ($(CONFIG_FILE),)
-include $(CONFIG_FILE)

# export for sub-makefiles
export CONFIG_CODE_COVERAGE

.PHONY: verify_config
verify_config:
	@if [ ! -r $(CONFIG_FILE) ]; then \
		echo 'Building $(firstword $(ALL)) requires a configuration file'; \
		echo '(.config). See README for more instructions. You can'; \
		echo 'run "cp defconfig .config" to create an example'; \
		echo 'configuration.'; \
		exit 1; \
	fi
VERIFY := verify_config
else
VERIFY :=
endif

# default target
.PHONY: _all
_all: $(VERIFY) $(ALL) $(EXTRA_TARGETS)

# continue setup
COVSUFFIX := $(if $(CONFIG_CODE_COVERAGE),-cov,)
PROJ := $(_PROJ)$(COVSUFFIX)

Q=@
E=echo
ifeq ($(V), 1)
Q=
E=true
endif
ifeq ($(QUIET), 1)
Q=@
E=true
endif

ifeq ($(Q),@)
MAKEFLAGS += --no-print-directory
endif

_DIRS := $(BUILDDIR)/$(PROJ)
.PHONY: _make_dirs
_make_dirs:
	@mkdir -p $(_DIRS)

$(BUILDDIR)/$(PROJ)/src/%.o: $(ROOTDIR)src/%.c | _make_dirs
	$(Q)$(CC) -c -o $@ $(CFLAGS) $<
	@$(E) "  CC " $<
$(BUILDDIR)/$(PROJ)/%.o: %.c | _make_dirs
	$(Q)$(CC) -c -o $@ $(CFLAGS) $<
	@$(E) "  CC " $<

BUILDOBJ = $(patsubst %,$(BUILDDIR)/$(PROJ)/%,$(patsubst $(ROOTDIR)%,%,$(1)))

.PHONY: common-clean
common-clean:
	$(Q)$(MAKE) -C $(ROOTDIR)/src clean
	$(Q)rm -rf $(ALL) $(BUILDDIR)/$(PROJ)