[PATCH 04/13] Makefile: Remove non-standard $(FLAGS) variable

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

FLAGS was introduced over the more standard CFLAGS, because there are some
options we can't compile without, so overriding CFLAGS from the command
line wasn't practical.  We've now better dealt with that using
BASE_CPPFLAGS, so there's no real need for FLAGS any more.  Replace it
with the more conventional CFLAGS, which now *can* be reasonable overridden
from the command line.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 Makefile | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/Makefile b/Makefile
index e89e5556..1e5f0282 100644
--- a/Makefile
+++ b/Makefile
@@ -36,8 +36,8 @@ BASE_CPPFLAGS := -D_XOPEN_SOURCE=700 -D_GNU_SOURCE \
 	-DVERSION=\"$(VERSION)\"
 CPPFLAGS := $(FORTIFY_FLAG) -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)
 
-FLAGS := -Wall -Wextra -Wno-format-zero-length -Wformat-security
-FLAGS += -pedantic -std=c11 -O2 -pie -fPIE
+WARNINGS = -Wall -Wextra -Wno-format-zero-length -Wformat-security
+CFLAGS = -pedantic -std=c11 -O2 -pie -fPIE $(WARNINGS)
 
 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 \
@@ -66,7 +66,7 @@ ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
 endif
 
 ifeq ($(shell :|$(CC) -fstack-protector-strong -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
-	FLAGS += -fstack-protector-strong
+	CFLAGS += -fstack-protector-strong
 endif
 
 prefix		?= /usr/local
@@ -85,7 +85,7 @@ endif
 
 all: $(BIN) $(MANPAGES) docs
 
-static: FLAGS += -static
+static: CFLAGS += -static
 static: CPPFLAGS += -DGLIBC_NO_STATIC_NSS
 static: clean all
 
@@ -96,12 +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) $(BASE_CPPFLAGS) $(CPPFLAGS) $(PASST_SRCS) -o passt $(LDFLAGS)
+	$(CC) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) $(PASST_SRCS) -o passt $(LDFLAGS)
 
-passt.avx2: FLAGS += -Ofast -mavx2 -ftree-vectorize -funroll-loops
+passt.avx2: CFLAGS += -Ofast -mavx2 -ftree-vectorize -funroll-loops
 passt.avx2: $(PASST_SRCS) $(HEADERS)
-	$(CC) $(filter-out -O2,$(FLAGS)) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) \
-		$(PASST_SRCS) -o passt.avx2 $(LDFLAGS)
+	$(CC) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) $(PASST_SRCS) -o passt.avx2 $(LDFLAGS)
 
 passt.avx2: passt
 
@@ -109,16 +108,16 @@ pasta.avx2 pasta.1 pasta: pasta%: passt%
 	ln -sf $< $@
 
 qrap: $(QRAP_SRCS) passt.h
-	$(CC) $(FLAGS) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) -DARCH=\"$(TARGET_ARCH)\" $(QRAP_SRCS) -o qrap $(LDFLAGS)
+	$(CC) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) -DARCH=\"$(TARGET_ARCH)\" $(QRAP_SRCS) -o qrap $(LDFLAGS)
 
 passt-repair: $(PASST_REPAIR_SRCS) seccomp_repair.h
-	$(CC) $(FLAGS) $(CFLAGS) $(BASE_CPPFLAGS) $(CPPFLAGS) $(PASST_REPAIR_SRCS) -o passt-repair $(LDFLAGS)
+	$(CC) $(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
+valgrind: CFLAGS += -g
 valgrind: CPPFLAGS += -DVALGRIND
 valgrind: all
 
-- 
2.53.0