From 5505161d8bc58964fab46be33c456ae753e9280e Mon Sep 17 00:00:00 2001
From: Moritz Warning <moritzwarning@web.de>
Date: Thu, 22 Jan 2015 22:24:39 +0100
Subject: [PATCH] allow environment variables to set/extend CC, CXX, CFLAGS and
 LDFLAGS

---
 make-freebsd.mk | 18 ++++++++++--------
 make-linux.mk   | 18 ++++++++++--------
 make-mac.mk     | 14 ++++++++------
 3 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/make-freebsd.mk b/make-freebsd.mk
index 2eea8eafb..b50efa813 100644
--- a/make-freebsd.mk
+++ b/make-freebsd.mk
@@ -1,5 +1,5 @@
-CC=cc
-CXX=c++
+CC?=cc
+CXX?=c++
 
 INCLUDES=
 DEFS=
@@ -21,19 +21,21 @@ endif
 # "make debug" is a shortcut for this
 ifeq ($(ZT_DEBUG),1)
 #	DEFS+=-DZT_TRACE -DZT_LOG_STDOUT 
-	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)
+ext/lz4/lz4.o node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CFLAGS?=-O2 CFLAGS+=-Wall -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 -pthread $(INCLUDES) -DNDEBUG $(DEFS)
+	LDFLAGS+=-pie -Wl,-z,relro,-z,now
 	STRIP=strip --strip-all
 endif
 
-CXXFLAGS=$(CFLAGS) -fno-rtti
+CXXFLAGS?=-fno-rtti
+CXXFLAGS=$(CFLAGS)
 
 all:	one
 
diff --git a/make-linux.mk b/make-linux.mk
index e0951711a..9719f36a2 100644
--- a/make-linux.mk
+++ b/make-linux.mk
@@ -1,6 +1,6 @@
 # Pick clang or gcc, with preference for clang
-CC=$(shell which clang gcc cc 2>/dev/null | head -n 1)
-CXX=$(shell which clang++ g++ c++ 2>/dev/null | head -n 1)
+CC?=$(shell which clang gcc cc 2>/dev/null | head -n 1)
+CXX?=$(shell which clang++ g++ c++ 2>/dev/null | head -n 1)
 
 INCLUDES=
 DEFS=
@@ -22,15 +22,16 @@ endif
 # "make debug" is a shortcut for this
 ifeq ($(ZT_DEBUG),1)
 #	DEFS+=-DZT_TRACE -DZT_LOG_STDOUT 
-	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)
+ext/lz4/lz4.o node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CFLAGS?=-O2 CFLAGS+=-Wall -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 -pthread $(INCLUDES) -DNDEBUG $(DEFS)
+	LDFLAGS+=-pie -Wl,-z,relro,-z,now
 	STRIP=strip --strip-all
 endif
 
@@ -39,7 +40,8 @@ endif
 #LDFLAGS=
 #STRIP=echo
 
-CXXFLAGS=$(CFLAGS) -fno-rtti
+CXXFLAGS?=-fno-rtti
+CXXFLAGS+=$(CFLAGS)
 
 all:	one
 
diff --git a/make-mac.mk b/make-mac.mk
index 854990bb9..c9e05c5a4 100644
--- a/make-mac.mk
+++ b/make-mac.mk
@@ -1,5 +1,5 @@
-CC=clang
-CXX=clang++
+CC?=clang
+CXX?=clang++
 
 INCLUDES=
 DEFS=
@@ -27,17 +27,19 @@ endif
 
 ifeq ($(ZT_DEBUG),1)
 #	DEFS+=-DZT_TRACE -DZT_LOG_STDOUT 
-	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)
+ext/lz4/lz4.o node/Salsa20.o node/SHA512.o node/C25519.o node/Poly1305.o: CFLAGS?=-O2 CFLAGS+=-Wall -g -pthread $(INCLUDES) $(DEFS)
 else
-	CFLAGS=-arch i386 -arch x86_64 -Wall -O3 -flto -fPIE -fvectorize -fstack-protector -pthread -mmacosx-version-min=10.6 -DNDEBUG -Wno-unused-private-field $(INCLUDES) $(DEFS)
+	CFLAGS?=-O3 -fstack-protector
+	CFLAGS+=-arch i386 -arch x86_64 -Wall -flto -fPIE -fvectorize -pthread -mmacosx-version-min=10.6 -DNDEBUG -Wno-unused-private-field $(INCLUDES) $(DEFS)
 	STRIP=strip
 endif
 
-CXXFLAGS=$(CFLAGS) -fno-rtti
+CXXFLAGS?=-fno-rtti
+CXXFLAGS=$(CFLAGS)
 
 all: one