From 235d4aba9ab4f461eebfba66e659212d034bab48 Mon Sep 17 00:00:00 2001
From: Moritz Warning <moritzwarning@web.de>
Date: Fri, 3 Jul 2015 20:18:19 +0200
Subject: [PATCH] allow environment variables to set/extend CC, CXX, CFLAGS and
 LDFLAGS

---
 make-freebsd.mk | 15 ++++++++-------
 make-linux.mk   | 15 ++++++++-------
 make-mac.mk     |  9 +++++----
 3 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/make-freebsd.mk b/make-freebsd.mk
index 90665e0e8..cc428ccbc 100644
--- a/make-freebsd.mk
+++ b/make-freebsd.mk
@@ -1,5 +1,5 @@
-CC=cc
-CXX=c++
+CC?=cc
+CXX?=c++
 
 INCLUDES=
 DEFS=
@@ -16,19 +16,20 @@ endif
 # "make debug" is a shortcut for this
 ifeq ($(ZT_DEBUG),1)
 	DEFS+=-DZT_TRACE 
-	CFLAGS=-Wall -g -pthread $(INCLUDES) $(DEFS)
-	LDFLAGS=
+	CFLAGS+=-Wall -g -pthread $(INCLUDES) $(DEFS)
+	LDFLAGS+=
 	STRIP=echo
 	# The following line enables optimization for the crypto code, since
 	# C25519 in particular is almost UNUSABLE in heavy testing without it.
 ext/lz4/lz4.o node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CFLAGS = -Wall -O2 -g -pthread $(INCLUDES) $(DEFS)
 else
-	CFLAGS=-Wall -O3 -fPIE -fvisibility=hidden -fstack-protector -pthread $(INCLUDES) -DNDEBUG $(DEFS)
-	LDFLAGS=-pie -Wl,-z,relro,-z,now
+	CFLAGS?=-O3 -fstack-protector
+	CFLAGS+=-Wall -fPIE -fvisibility=hidden -fstack-protector -pthread $(INCLUDES) -DNDEBUG $(DEFS)
+	LDFLAGS+=-pie -Wl,-z,relro,-z,now
 	STRIP=strip --strip-all
 endif
 
-CXXFLAGS=$(CFLAGS) -fno-rtti
+CXXFLAGS+=$(CFLAGS) -fno-rtti
 
 all:	one
 
diff --git a/make-linux.mk b/make-linux.mk
index 6881926b0..18000c6c6 100644
--- a/make-linux.mk
+++ b/make-linux.mk
@@ -18,9 +18,8 @@
 #
 
 # Automagically pick clang or gcc, with preference for clang
-CC=$(shell if [ -e /usr/bin/clang ]; then echo clang; else echo gcc; fi)
-CXX=$(shell if [ -e /usr/bin/clang++ ]; then echo clang++; else echo g++; fi)
-
+CC?=$(shell if [ -e /usr/bin/clang ]; then echo clang; else echo gcc; fi)
+CXX?=$(shell if [ -e /usr/bin/clang++ ]; then echo clang++; else echo g++; fi)
 INCLUDES=
 DEFS=
 LIBS=
@@ -43,16 +42,18 @@ endif
 # "make debug" is a shortcut for this
 ifeq ($(ZT_DEBUG),1)
 	DEFS+=-DZT_TRACE 
-	CFLAGS=-Wall -g -pthread $(INCLUDES) $(DEFS)
-	CXXFLAGS=-Wall -g -pthread $(INCLUDES) $(DEFS)
+	CFLAGS+=-Wall -g -pthread $(INCLUDES) $(DEFS)
+	CXXFLAGS+=-Wall -g -pthread $(INCLUDES) $(DEFS)
 	LDFLAGS=
 	STRIP=echo
 	# The following line enables optimization for the crypto code, since
 	# C25519 in particular is almost UNUSABLE in -O0 even on a 3ghz box!
 ext/lz4/lz4.o node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CFLAGS = -Wall -O2 -g -pthread $(INCLUDES) $(DEFS)
 else
-	CFLAGS=-Wall -O3 -fPIE -fvisibility=hidden -fstack-protector -pthread $(INCLUDES) -DNDEBUG $(DEFS)
-	CXXFLAGS=-Wall -O3 -fPIE -fvisibility=hidden -fstack-protector -fno-rtti -pthread $(INCLUDES) -DNDEBUG $(DEFS)
+	CFLAGS?=-O3 -fstack-protector
+	CFLAGS+=-Wall -fPIE -fvisibility=hidden -pthread $(INCLUDES) -DNDEBUG $(DEFS)
+	CXXFLAGS?=-O3 -fstack-protector
+	CXXFLAGS+=-Wall -fPIE -fvisibility=hidden -fno-rtti -pthread $(INCLUDES) -DNDEBUG $(DEFS)
 	LDFLAGS=-pie -Wl,-z,relro,-z,now
 	STRIP=strip --strip-all
 endif
diff --git a/make-mac.mk b/make-mac.mk
index 09fd1e36f..1bc842cee 100644
--- a/make-mac.mk
+++ b/make-mac.mk
@@ -1,5 +1,5 @@
-CC=clang
-CXX=clang++
+CC?=clang
+CXX?=clang++
 
 INCLUDES=-I/usr/local/include
 DEFS=
@@ -38,13 +38,14 @@ endif
 # Debug mode -- dump trace output, build binary with -g
 ifeq ($(ZT_DEBUG),1)
 	DEFS+=-DZT_TRACE 
-	CFLAGS=-Wall -g -pthread $(INCLUDES) $(DEFS)
+	CFLAGS+=-Wall -g -pthread $(INCLUDES) $(DEFS)
 	STRIP=echo
 	# The following line enables optimization for the crypto code, since
 	# C25519 in particular is almost UNUSABLE in heavy testing without it.
 ext/lz4/lz4.o node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CFLAGS = -Wall -O2 -g -pthread $(INCLUDES) $(DEFS)
 else
-	CFLAGS=$(ARCH_FLAGS) -Wall -O3 -flto -fPIE -fvectorize -fstack-protector -pthread -mmacosx-version-min=10.7 -DNDEBUG -Wno-unused-private-field $(INCLUDES) $(DEFS)
+	CFLAGS?=-O3 -fstack-protector
+	CFLAGS+=$(ARCH_FLAGS) -Wall -flto -fPIE -fvectorize -pthread -mmacosx-version-min=10.7 -DNDEBUG -Wno-unused-private-field $(INCLUDES) $(DEFS)
 	STRIP=strip
 endif