From 613e984d8c2af11f8491253217ab6f2ee6daacf0 Mon Sep 17 00:00:00 2001
From: meator <coder64@protonmail.com>
Date: Mon, 23 Aug 2021 20:08:46 +0200
Subject: [PATCH] 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      | 28 ++++++++++++++++------------
 config.mk     | 22 +++++++++++++++++-----
 demo/Makefile |  5 +++--
 test/Makefile |  6 +++---
 4 files changed, 39 insertions(+), 22 deletions(-)

diff --git a/Makefile b/Makefile
index 58aa14f..3c3f36f 100644
--- a/Makefile
+++ b/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
diff --git a/config.mk b/config.mk
index 2beaafd..105a7f0 100644
--- a/config.mk
+++ b/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)
diff --git a/demo/Makefile b/demo/Makefile
index 8b6d52f..aa34cfb 100644
--- a/demo/Makefile
+++ b/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
 
diff --git a/test/Makefile b/test/Makefile
index 21635f9..b9c0f07 100644
--- a/test/Makefile
+++ b/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))))