build: Don't conflict with the user's CFLAGS (#136)

This uses the variable MAINT_CFLAGS to set the project's flags so that
the user can set CFLAGS as an environment variable or as an make
argument without any conflicts.

This can be problemtic with the build environment in some distros.

src/Makefile

@@ -60,20 +60,21 @@ ifeq ($(OS_ARCH),Darwin)
 endif
 
 PREFIX ?= /usr
-CFLAGS = -g -DXP_UNIX -Wall -DVERSION=$(VERSION)
+MAINT_CFLAGS := -g -DXP_UNIX -Wall -DVERSION=$(VERSION)
 
 ifndef PYTHON
   PYTHON = python
 endif
 
 # Spidermonkey library.
-CFLAGS += -Ispidermonkey/js/src
+MAINT_CFLAGS += -Ispidermonkey/js/src
 
 LIBRARY_LINK = $(LIBRARY_NAME).$(SO_SUFFIX)
 PREFIX := $(DESTDIR)$(PREFIX)
 LIB_PREFIX = $(PREFIX)/lib
 INC_PREFIX = $(PREFIX)/include
 BIN_PREFIX = $(PREFIX)/bin
+DOC_PREFIX = $(PREFIX)/share/doc/pacparser
 MAN_PREFIX = $(PREFIX)/share/man
 
 .PHONY: clean pymod install-pymod
@@ -87,17 +88,17 @@ spidermonkey/libjs.a: spidermonkey/js/src
 	cd spidermonkey && SMCFLAGS="$(SHFLAGS) $(SMCFLAGS)" $(MAKE) jslib
 
 pacparser.o: pacparser.c pac_utils.h pacparser.h jsapi_buildstamp
-	$(CC) $(CFLAGS) $(SHFLAGS) -c pacparser.c -o pacparser.o
+	$(CC) $(MAINT_CFLAGS) $(CFLAGS) $(SHFLAGS) -c pacparser.c -o pacparser.o
 	touch pymod/pacparser_o_buildstamp
 
 $(LIBRARY): pacparser.o spidermonkey/libjs.a
-	$(MKSHLIB) $(CFLAGS) $(LDFLAGS) $(LIB_OPTS) -o $(LIBRARY) pacparser.o spidermonkey/libjs.a -lm
+	$(MKSHLIB) $(MAINT_CFLAGS) $(CFLAGS) $(LDFLAGS) $(LIB_OPTS) -o $(LIBRARY) pacparser.o spidermonkey/libjs.a -lm
 
 $(LIBRARY_LINK): $(LIBRARY)
 	ln -sf $(LIBRARY) $(LIBRARY_LINK)
 
 pactester: pactester.c pacparser.h pacparser.o spidermonkey/libjs.a
-	$(CC) $(CFLAGS) $(LDFLAGS) pactester.c pacparser.o spidermonkey/libjs.a -o pactester -lm -L. -I.
+	$(CC) $(MAINT_CFLAGS) $(CFLAGS) $(LDFLAGS) pactester.c pacparser.o spidermonkey/libjs.a -o pactester -lm -L. -I.
 
 testpactester: pactester $(LIBRARY_LINK)
 	echo "Running tests for pactester."
@@ -119,11 +120,11 @@ install: all
 	install -d $(MAN_PREFIX)/man3/
 	(test -d ../docs && install -m 644 ../docs/man/man3/*.3 $(MAN_PREFIX)/man3/) || true
 	# install html docs
-	install -d $(PREFIX)/share/doc/pacparser/html/
-	(test -d ../docs/html && install -m 644 ../docs/html/* $(PREFIX)/share/doc/pacparser/html/) || true
+	install -d $(DOC_PREFIX)/html/
+	(test -d ../docs/html && install -m 644 ../docs/html/* $(DOC_PREFIX)/html/) || true
 	# install examples
-	install -d $(PREFIX)/share/doc/pacparser/examples/
-	(test -d ../examples && install -m 644 ../examples/* $(PREFIX)/share/doc//pacparser/examples/) || true
+	install -d $(DOC_PREFIX)/examples/
+	(test -d ../examples && install -m 644 ../examples/* $(DOC_PREFIX)/examples/) || true
 
 # Targets to build python module
 pymod: pacparser.o pacparser.h spidermonkey/libjs.a