lib: recursive makefiles considered harmful (tm)

Signed-off-by: Alejandro Mery <amery@geeks.cl>

lib/Makefile

+.PHONY: all libs
+
+CC = gcc
+AR = ar
+
+srctree	?= ..
+O	?= $(srctree)/out
+
+OBJDIR	:= $(O)/lib
+DEPS	:= $(OBJDIR)/deps.mk
+
+INCLUDES = -I$(srctree)/include
+CFLAGS	 = -O2
+CFLAGS  += -Wall -Wextra -std=c99 -D_POSIX_C_SOURCE=200112L
+CFLAGS  += $(INCLUDES)
+
+SRCS	:=
+
+all: libs
+
+include libfex/Makefile
+
+# *.a
+%.a:
+	@mkdir -vp $(@D)
+	$(AR) rcs $@ $^
+
+# *.o
+%.o: SRC=$(patsubst $(OBJDIR)/%.o,%.c,$@)
+%.o:
+	@mkdir -vp $(@D)
+	$(CC) $(CFLAGS) -c -o $@ $(SRC)
+
+# dependencies
+$(DEPS): Makefile libfex/Makefile
+	mkdir -p $(@D)
+	for x in $(SRCS); do \
+		$(CC) -MM -MT $(OBJDIR)/$${x%.c}.o $$x $(INCLUDES); \
+	done > $@~
+	mv $@~ $@
+
+include $(DEPS)

lib/libfex/Makefile

-CC = gcc
-AR = ar
+libfex_SOURCES	:= $(wildcard libfex/*.c)
+libfex_OBJS	:= $(patsubst %.c,$(OBJDIR)/%.o,$(libfex_SOURCES))
+libfex_LIB	:= $(O)/libfex.a
 
-srctree	?= ../..
-O	?= $(srctree)/out
+SRCS	+= $(libfex_SOURCES)
+OBJS	+= $(libfex_OBJS)
 
-OBJDIR	:= $(O)/libfex
-LIBFEX	:= $(O)/libfex.a
+libs: $(libfex_LIB)
 
-SRCS	:= $(wildcard *.c)
-OBJS	:= $(patsubst %.c,$(OBJDIR)/%.o,$(SRCS))
-
-INCLUDES = -I$(srctree)/include
-CFLAGS	 = -O2
-CFLAGS  += -Wall -Wextra -std=c99 -D_POSIX_C_SOURCE=200112L
-CFLAGS  += $(INCLUDES)
-
-DEPS	:= $(OBJDIR)/deps.mk
-
-# libfex.a
-$(LIBFEX): $(OBJS)
-	@mkdir -vp $(@D)
-	$(AR) rcs $@ $^
-
-# out/foo.o: foo.c
-$(OBJS): SRC=$(patsubst $(OBJDIR)/%.o,%.c,$@)
-$(OBJS):
-	@mkdir -vp $(@D)
-	$(CC) $(CFLAGS) -c -o $@ $(SRC)
-
-# dependencies
-$(DEPS): Makefile
-	mkdir -p $(@D)
-	for x in $(SRCS); do \
-		$(CC) -MM -MT $(OBJDIR)/$${x%.c}.o $$x $(INCLUDES); \
-	done > $@~
-	mv $@~ $@
-
-include $(DEPS)
+$(libfex_LIB): $(libfex_OBJS)