Improve Makefile

This commit adds some features mentioned in General Conventions for
Makefiles from the GNU make manual. It also allows the Makefile to
use some variables form the environment.

Makefile

@@ -3,7 +3,7 @@ include config.mk
 .PHONY: all shared install uninstall test demo clean distclean
 
 %.o: %.c
-	$(CC) -c $(CFLAGS) $<
+	$(CC) -c $(ALL_CFLAGS) $<
 
 all: changelog shared
 
@@ -20,35 +20,39 @@ install: shared
 	install -D $(LIB_NAME) $(DESTDIR)$(LIBDIR)/$(LIB_NAME)
 	ln -snf $(LIB_NAME) $(DESTDIR)$(LIBDIR)/$(LIB_SONAME)
 	ln -snf $(LIB_SONAME) $(DESTDIR)$(LIBDIR)/$(LIBX86).so
-	install -m 644 -D include/x86emu.h $(DESTDIR)/usr/include/x86emu.h
+	install -m 644 -D include/x86emu.h $(DESTDIR)$(INCLUDEDIR)/x86emu.h
+	if [ "$(OLDINCLUDEDIR)" -a "$(OLDINCLUDEDIR)" != "$(INCLUDEDIR)" ] ; then\
+		install -m 644 -D include/x86emu.h $(DESTDIR)$(OLDINCLUDEDIR)/x86emu.h ;\
+	fi
 
 uninstall:
 	rm -f $(DESTDIR)$(LIBDIR)/$(LIB_NAME)
 	rm -f $(DESTDIR)$(LIBDIR)/$(LIB_SONAME)
 	rm -f $(DESTDIR)$(LIBDIR)/$(LIBX86).so
-	rm -f $(DESTDIR)/usr/include/x86emu.h
+	rm -f $(DESTDIR)$(INCLUDEDIR)/x86emu.h
+	rm -f $(DESTDIR)$(OLDINCLUDEDIR)/x86emu.h
 
 $(LIB_NAME): .depend $(OBJS)
-	$(CC) -shared -Wl,-soname,$(LIB_SONAME) $(OBJS) -o $(LIB_NAME) $(LDFLAGS)
+	$(CC) -shared -Wl,-soname,$(LIB_SONAME) $(ALL_CFLAGS) $(OBJS) -o $(LIB_NAME) $(LDFLAGS)
 	@ln -snf $(LIB_NAME) $(LIB_SONAME)
 	@ln -snf $(LIB_SONAME) $(LIBX86).so
 
 test:
-	make -C test
+	$(MAKE) -C test
 
 demo:
-	make -C demo
+	$(MAKE) -C demo
 
 archive: changelog
 	@if [ ! -d .git ] ; then echo no git repo ; false ; fi
 	mkdir -p package
-	git archive --prefix=$(PREFIX)/ $(BRANCH) > package/$(PREFIX).tar
-	tar -r -f package/$(PREFIX).tar --mode=0664 --owner=root --group=root --mtime="`git show -s --format=%ci`" --transform='s:^:$(PREFIX)/:' VERSION changelog
-	xz -f package/$(PREFIX).tar
+	git archive --prefix=$(ARCHIVE_PREFIX)/ $(BRANCH) > package/$(ARCHIVE_PREFIX).tar
+	tar -r -f package/$(ARCHIVE_PREFIX).tar --mode=0664 --owner=root --group=root --mtime="`git show -s --format=%ci`" --transform='s:^:$(ARCHIVE_PREFIX)/:' VERSION changelog
+	xz -f package/$(ARCHIVE_PREFIX).tar
 
 clean:
-	make -C test clean
-	make -C demo clean
+	$(MAKE) -C test clean
+	$(MAKE) -C demo clean
 	rm -f *.o *~ include/*~ *.so.* *.so .depend
 	rm -rf package
 
@@ -57,6 +61,6 @@ distclean: clean
 
 ifneq "$(MAKECMDGOALS)" "clean"
 .depend: $(CFILES)
-	@$(CC) -MG -MM $(CFLAGS) $(CFILES) >$@
+	@$(CC) -MG -MM $(ALL_CFLAGS) $(CFILES) >$@
 -include .depend
 endif

config.mk

@@ -1,3 +1,4 @@
+SHELL = /bin/sh
 ARCH	:= $(shell uname -m)
 ifneq ($(filter i386 i486 i586 i686, $(ARCH)),)
 ARCH	:= i386
@@ -11,15 +12,26 @@ VERSION := $(shell $(GIT2LOG) --version VERSION ; cat VERSION)
 endif
 GITDEPS := $(shell [ -d .git ] && echo .git/HEAD .git/refs/heads .git/refs/tags)
 BRANCH  := $(shell [ -d .git ] && git branch | perl -ne 'print $$_ if s/^\*\s*//')
-PREFIX  := libx86emu-$(VERSION)
+ARCHIVE_PREFIX  := libx86emu-$(VERSION)
+
+PREFIX ?= /usr/local
+EXEC_PREFIX ?= $(PREFIX)
+ifeq "$(ARCH)" "x86_64"
+LIBDIR ?= $(EXEC_PREFIX)/lib64
+else
+LIBDIR ?= $(EXEC_PREFIX)/lib
+endif
+INCLUDEDIR ?= $(PREFIX)/include
+OLDINCLUDEDIR ?= /usr/include
 
 MAJOR_VERSION := $(shell cut -d . -f 1 VERSION)
 
-CC	= gcc
-CFLAGS	= -g -O2 -fPIC -fvisibility=hidden -fomit-frame-pointer -Wall
-LDFLAGS =
+CC	?= gcc
+CFLAGS	?= -g -O2 -Wall -fomit-frame-pointer
+ALL_CFLAGS	= -fPIC -fvisibility=hidden $(CFLAGS)
+
+export CC CFLAGS ARCH
 
-LIBDIR = /usr/lib$(shell ldd /bin/sh | grep -q /lib64/ && echo 64)
 LIBX86	= libx86emu
 
 CFILES	= $(wildcard *.c)

demo/Makefile

@@ -1,5 +1,6 @@
-CC         = gcc
-CFLAGS     = -g -Wall -fomit-frame-pointer -O2
+SHELL      = /bin/sh
+CC         ?= gcc
+CFLAGS     ?= -g -Wall -fomit-frame-pointer -O2
 
 .PHONY: clean
 

test/Makefile

@@ -1,6 +1,6 @@
-CC         = gcc
-CFLAGS     = -g -Wall -fomit-frame-pointer -O2
-LDFLAGS    =
+SHELL      = /bin/sh
+CC         ?= gcc
+CFLAGS     ?= -g -Wall -fomit-frame-pointer -O2
 TST_FILES  = $(sort $(wildcard *.tst))
 INIT_FILES = $(addsuffix .init,$(basename $(wildcard *.tst)))
 RES_FILES  = $(sort $(addsuffix .result,$(basename $(wildcard *.tst))))