[PATCH 03/13] Makefile: Remove preprocessor flags from $(FLAGS)

[David Gibson <david@gibson.dropbear.id.au>]

FLAGS contains both compiler and preprocessor flags, which isn't great
make practice.  Move preprocessor flags out of that variable and into the
more conventionally named $(CPPFLAGS).  Use both $(BASE_CPPFLAGS) and
$(CPPFLAGS) in most places, so we get both the essential flags and the
conditional ones (which could be overridden on the command line).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 Makefile | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/Makefile b/Makefile
index 0de98375..e89e5556 100644
--- a/Makefile
+++ b/Makefile
@@ -34,12 +34,10 @@ endif
 BASE_CPPFLAGS := -D_XOPEN_SOURCE=700 -D_GNU_SOURCE \
 	-DPAGE_SIZE=$(shell getconf PAGE_SIZE) \
 	-DVERSION=\"$(VERSION)\"
+CPPFLAGS := $(FORTIFY_FLAG) -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)
 
 FLAGS := -Wall -Wextra -Wno-format-zero-length -Wformat-security
-FLAGS += -pedantic -std=c11
-FLAGS +=  $(FORTIFY_FLAG) -O2 -pie -fPIE
-FLAGS += $(BASE_CPPFLAGS)
-FLAGS += -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)
+FLAGS += -pedantic -std=c11 -O2 -pie -fPIE
 
 PASST_SRCS = arch.c arp.c bitmap.c checksum.c conf.c dhcp.c dhcpv6.c \
 	epoll_ctl.c flow.c fwd.c fwd_rule.c icmp.c igmp.c inany.c iov.c ip.c \
@@ -64,7 +62,7 @@ HEADERS = $(PASST_HEADERS) seccomp.h
 
 C := \#include <sys/random.h>\nint main(){int a=getrandom(0, 0, 0);}
 ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
-	FLAGS += -DHAS_GETRANDOM
+	CPPFLAGS += -DHAS_GETRANDOM
 endif
 
 ifeq ($(shell :|$(CC) -fstack-protector-strong -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
@@ -87,7 +85,8 @@ endif
 
 all: $(BIN) $(MANPAGES) docs
 
-static: FLAGS += -static -DGLIBC_NO_STATIC_NSS
+static: FLAGS += -static
+static: CPPFLAGS += -DGLIBC_NO_STATIC_NSS
 static: clean all
 
 seccomp.h: seccomp.sh $(PASST_SRCS) $(PASST_HEADERS)
@@ -97,11 +96,11 @@ seccomp_repair.h: seccomp.sh $(PASST_REPAIR_SRCS)
 	@ ARCH="$(TARGET_ARCH)" CC="$(CC)" ./seccomp.sh seccomp_repair.h $(PASST_REPAIR_SRCS)
 
 passt: $(PASST_SRCS) $(HEADERS)
-	$(CC) $(FLAGS) $(CFLAGS) $(CPPFLAGS) $(PASST_SRCS) -o passt $(LDFLAGS)
+	$(CC) $(FLAGS) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) $(PASST_SRCS) -o passt $(LDFLAGS)
 
 passt.avx2: FLAGS += -Ofast -mavx2 -ftree-vectorize -funroll-loops
 passt.avx2: $(PASST_SRCS) $(HEADERS)
-	$(CC) $(filter-out -O2,$(FLAGS)) $(CFLAGS) $(CPPFLAGS) \
+	$(CC) $(filter-out -O2,$(FLAGS)) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) \
 		$(PASST_SRCS) -o passt.avx2 $(LDFLAGS)
 
 passt.avx2: passt
@@ -110,16 +109,17 @@ pasta.avx2 pasta.1 pasta: pasta%: passt%
 	ln -sf $< $@
 
 qrap: $(QRAP_SRCS) passt.h
-	$(CC) $(FLAGS) $(CFLAGS) $(CPPFLAGS) -DARCH=\"$(TARGET_ARCH)\" $(QRAP_SRCS) -o qrap $(LDFLAGS)
+	$(CC) $(FLAGS) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) -DARCH=\"$(TARGET_ARCH)\" $(QRAP_SRCS) -o qrap $(LDFLAGS)
 
 passt-repair: $(PASST_REPAIR_SRCS) seccomp_repair.h
-	$(CC) $(FLAGS) $(CFLAGS) $(CPPFLAGS) $(PASST_REPAIR_SRCS) -o passt-repair $(LDFLAGS)
+	$(CC) $(FLAGS) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) $(PASST_REPAIR_SRCS) -o passt-repair $(LDFLAGS)
 
 valgrind: EXTRA_SYSCALLS += rt_sigprocmask rt_sigtimedwait rt_sigaction	\
 			    rt_sigreturn getpid gettid kill clock_gettime \
 			    mmap|mmap2 munmap open unlink gettimeofday futex \
 			    statx readlink
-valgrind: FLAGS += -g -DVALGRIND
+valgrind: FLAGS += -g
+valgrind: CPPFLAGS += -DVALGRIND
 valgrind: all
 
 .PHONY: clean
@@ -182,8 +182,7 @@ CLANG_TIDY = clang-tidy
 CLANG_TIDY_FLAGS = -DCLANG_TIDY_58992
 
 clang-tidy: $(PASST_SRCS)
-	$(CLANG_TIDY) $^ -- $(filter-out -pie,$(FLAGS) $(CFLAGS) $(CPPFLAGS)) \
-		$(CLANG_TIDY_FLAGS)
+	$(CLANG_TIDY) $^ -- $(BASE_CPPFLAGS) $(CPPFLAGS) $(CLANG_TIDY_FLAGS)
 
 CPPCHECK = cppcheck
 CPPCHECK_FLAGS = --std=c11 --error-exitcode=1 --enable=all --force	\
-- 
2.53.0