Adhere to GNU Make directory variables

Makefile

@@ -9,9 +9,13 @@ VERSION = $(MAJOR_VERSION).$(MINOR_VERSION).$(PATCH_VERSION)
 PROJECT_SO = $(PROJECT).so.$(VERSION)
 PROJECT_SO_FQ = $(PROJECT).so.$(MAJOR_VERSION)
 PROJECT_SO_NV = $(PROJECT).so
-PREFIX = /usr/local
-DST = $(PREFIX)/lib
-PC_DST = $(DST)/pkgconfig
+prefix = /usr/local
+exec_prefix = $(prefix)
+includedir = $(prefix)/include
+datarootdir = $(prefix)/share
+mandir = $(datarootdir)/man
+libdir = $(exec_prefix)/lib
+pkgcfgdir = $(libdir)/pkgconfig
 O = -Og
 CDEFS = -D_FILE_OFFSET_BITS=64 # Required for large file support on 32-bit.
 CFLAGS = $(O) $(CDEFS) -g -Iinclude -Idynstr/include -fPIC -MD -MF $(@:.o=.d)
@@ -26,16 +30,20 @@ OBJECTS = \
 
 all: $(PROJECT_A) $(PROJECT_SO)
 
-install: all $(PC_DST)/libweb.pc
-	mkdir -p $(PREFIX)/include
-	cp -R include/libweb $(PREFIX)/include
-	chmod 0644 $(PREFIX)/include/libweb/*.h
-	mkdir -p $(DST)
-	cp $(PROJECT_A) $(PROJECT_SO) $(DST)
-	chmod 0755 $(DST)/$(PROJECT_A) $(DST)/$(PROJECT_SO)
-	ln -fs $(DST)/$(PROJECT_SO) $(DST)/$(PROJECT_SO_FQ)
-	ln -fs $(DST)/$(PROJECT_SO) $(DST)/$(PROJECT_SO_NV)
-	+cd doc && $(MAKE) PREFIX=$(PREFIX) install
+install: all $(pkgcfgdir)/libweb.pc
+	mkdir -p $(DESTDIR)$(includedir)
+	cp -R include/libweb $(DESTDIR)$(includedir)
+	chmod 0644  $(DESTDIR)$(includedir)/libweb/*.h
+	mkdir -p $(DESTDIR)$(libdir)
+	cp $(PROJECT_A) $(PROJECT_SO) $(DESTDIR)$(libdir)
+	chmod 0755 $(libdir)/$(PROJECT_A) $(DESTDIR)$(libdir)/$(PROJECT_SO)
+	ln -fs $(libdir)/$(PROJECT_SO) $(DESTDIR)$(libdir)/$(PROJECT_SO_FQ)
+	ln -fs $(libdir)/$(PROJECT_SO) $(DESTDIR)$(libdir)/$(PROJECT_SO_NV)
+	+cd doc && $(MAKE) install \
+		DESTDIR=$(DESTDIR) \
+		prefix=$(prefix) \
+		datarootdir=$(datarootdir) \
+		mandir=$(mandir)
 
 clean:
 	rm -f $(OBJECTS) $(DEPS)
@@ -52,9 +60,9 @@ $(PROJECT_A): $(OBJECTS)
 $(PROJECT_SO): $(OBJECTS)
 	$(CC) $(LDFLAGS) $(OBJECTS) -o $@
 
-$(PC_DST)/libweb.pc: libweb.pc
-	mkdir -p $(PC_DST)
-	sed -e 's,/usr/local,$(PREFIX),' $< > $@
+$(pkgcfgdir)/libweb.pc: libweb.pc
+	mkdir -p $(pkgcfgdir)
+	sed -e 's,/usr/local,$(prefix),' $< > $@
 	chmod 0644 $@
 
 -include $(DEPS)

doc/Makefile

@@ -1,9 +1,19 @@
 .POSIX:
 
-PREFIX = /usr/local
+prefix = /usr/local
+datarootdir = $(prefix)/share
+mandir = $(datarootdir)/man
 
 all:
 
 install: all
-	+cd man3 && $(MAKE) PREFIX=$(PREFIX) install
-	+cd man7 && $(MAKE) PREFIX=$(PREFIX) install
+	+cd man3 && $(MAKE) install \
+		DESTDIR=$(DESTDIR) \
+		prefix=$(prefix) \
+		datarootdir=$(datarootdir) \
+		mandir=$(mandir)
+	+cd man7 && $(MAKE) install \
+		DESTDIR=$(DESTDIR) \
+		prefix=$(prefix) \
+		datarootdir=$(datarootdir) \
+		mandir=$(mandir)

doc/man3/Makefile

@@ -1,32 +1,34 @@
 .POSIX:
 
-PREFIX = /usr/local
-DST = $(PREFIX)/share/man/man3
+prefix = /usr/local
+datarootdir = $(prefix)/share
+mandir = $(datarootdir)/man
+man3dir = $(mandir)/man3
 OBJECTS = \
-	$(DST)/handler_add.3 \
-	$(DST)/handler_alloc.3 \
-	$(DST)/handler_free.3 \
-	$(DST)/handler_listen.3 \
-	$(DST)/html_node_add_attr.3 \
-	$(DST)/html_node_add_child.3 \
-	$(DST)/html_node_add_sibling.3 \
-	$(DST)/html_node_alloc.3 \
-	$(DST)/html_node_free.3 \
-	$(DST)/html_node_set_value.3 \
-	$(DST)/html_node_set_value_unescaped.3 \
-	$(DST)/html_serialize.3 \
-	$(DST)/http_alloc.3 \
-	$(DST)/http_cookie_create.3 \
-	$(DST)/http_encode_url.3 \
-	$(DST)/http_free.3 \
-	$(DST)/http_response_add_header.3 \
-	$(DST)/http_update.3
+	$(DESTDIR)$(man3dir)/handler_add.3 \
+	$(DESTDIR)$(man3dir)/handler_alloc.3 \
+	$(DESTDIR)$(man3dir)/handler_free.3 \
+	$(DESTDIR)$(man3dir)/handler_listen.3 \
+	$(DESTDIR)$(man3dir)/html_node_add_attr.3 \
+	$(DESTDIR)$(man3dir)/html_node_add_child.3 \
+	$(DESTDIR)$(man3dir)/html_node_add_sibling.3 \
+	$(DESTDIR)$(man3dir)/html_node_alloc.3 \
+	$(DESTDIR)$(man3dir)/html_node_free.3 \
+	$(DESTDIR)$(man3dir)/html_node_set_value.3 \
+	$(DESTDIR)$(man3dir)/html_node_set_value_unescaped.3 \
+	$(DESTDIR)$(man3dir)/html_serialize.3 \
+	$(DESTDIR)$(man3dir)/http_alloc.3 \
+	$(DESTDIR)$(man3dir)/http_cookie_create.3 \
+	$(DESTDIR)$(man3dir)/http_encode_url.3 \
+	$(DESTDIR)$(man3dir)/http_free.3 \
+	$(DESTDIR)$(man3dir)/http_response_add_header.3 \
+	$(DESTDIR)$(man3dir)/http_update.3
 
 all:
 
 install: $(OBJECTS)
 
-$(DST)/%.3: %.3
-	mkdir -p $(DST)
+$(DESTDIR)$(man3dir)/%.3: %.3
+	mkdir -p $(DESTDIR)$(man3dir)
 	cp $< $@
 	chmod 0644 $@

doc/man7/Makefile

@@ -1,17 +1,19 @@
 .POSIX:
 
-PREFIX = /usr/local
-DST = $(PREFIX)/share/man/man7
+prefix = /usr/local
+datarootdir = $(prefix)/share
+mandir = $(datarootdir)/man
+man7dir = $(mandir)/man7
 OBJECTS = \
-	$(DST)/libweb_handler.7 \
-	$(DST)/libweb_html.7 \
-	$(DST)/libweb_http.7
+	$(DESTDIR)$(man7dir)/libweb_handler.7 \
+	$(DESTDIR)$(man7dir)/libweb_html.7 \
+	$(DESTDIR)$(man7dir)/libweb_http.7
 
 all:
 
 install: $(OBJECTS)
 
-$(DST)/%.7: %.7
-	mkdir -p $(DST)
+$(DESTDIR)$(man7dir)/%.7: %.7
+	mkdir -p $(DESTDIR)$(man7dir)
 	cp $< $@
 	chmod 0644 $@