ECHO=echo

ifndef OS
OS=$(shell uname)
endif

CFLAGS=-Wall -pedantic -std=c99 -O2 -g -DASSERT_CORE -DHAVE_HSTRERROR 
ifeq ($(OS), FreeBSD)
CFLAGS+= -DHAVE_POLL_H
endif

ifeq ($(OS), Linux)
CFLAGS+= -DHAVE_SYS_POLL_H -D_GNU_SOURCE -D_LARGE_FILES -D_FILE_OFFSET_BITS=64
endif

CFLAGS+=$(EXTRAFLAGS)

CC=gcc
AR=ar
RANLIB=ranlib
LD=ld
LIB=-lm $(EXTRALIB)


INCLUDE=-I$(topbuilddir)/include -I. $(EXTRAINCLUDE) 
ARFLAGS=rcv
LDFLAGS=-r

ifdef SUBOBJ
SUBSYS=SUBSYS.o
endif 

ifdef SUBDIRS
SUBDIROBJS  := $(SUBDIRS:%=%/SUBSYS.o)
endif

.SUFFIXES: .o.c

.c.o:
	$(CC) $(CFLAGS) $(INCLUDE) -c $<

all: $(SUBSYS) $(LIBRARY) $(PROGRAM)

define prog_dep
 $(1): $$(PROGRAMOBJ_$(1))
endef

$(foreach prog,$(PROGRAM),$(eval $(call prog_dep,$(prog))))

ifdef PROGRAM
ifdef LIBRARY
$(PROGRAM): $(LIBRARY)
endif

$(PROGRAM): %: %.o 
	$(CC) -o $@ $< $(PROGRAMOBJ_$(@)) $(LIBRARY) $(LIB) 
endif

ifdef LIBRARY
$(LIBRARY): $(LIBOBJ) $(SUBDIROBJS)
	$(AR) $(ARFLAGS) $@ $(LIBOBJ) $(SUBDIROBJS) 
	$(RANLIB) $@
endif

ifdef SUBOBJ
$(SUBSYS): $(SUBOBJ)
	$(LD) $(LDFLAGS) -o $@ $(SUBOBJ)
endif

ifdef SUBDIRS
$(SUBDIROBJS): $(SUBDIRS:%=%-recursive) ;

$(SUBDIRS:%=%-recursive):
	$(MAKE) -C $(subst -recursive,,$@) -f Makefile OS=$(OS) SUBSYS.o
endif
 
clean:
ifdef LIBOBJ
	rm -rf $(LIBOBJ)
endif 
ifdef PROGRAM
	rm -rf $(PROGRAM)
	rm -rf $(foreach P, $(PROGRAM), $P.o $(PROGRAMOBJ_$(P)))
	rm -rf *core core.*
endif
ifdef LIBRARY
	rm -rf $(LIBRARY)
endif
ifdef SUBOBJ
	rm -rf $(SUBOBJ) $(SUBSYS)
endif
ifdef SUBDIRS
	for dir in $(SUBDIRS); do $(MAKE) -f Makefile -C $$dir OS=$(OS) clean || exit; done
endif