From f6a696d090852a4aa8ec8c02108c0601d44b563c Mon Sep 17 00:00:00 2001
From: Guillem Jover <guillem@hadrons.org>
Date: Sun, 12 Apr 2020 04:01:27 +0200
Subject: [PATCH] [PATCH] build: Honor user build flags
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CPPFLAGS, CFLAGS and LDFLAGS are user flags, which we need to preserve,
regardless of the user passing them over the environment or the
command-line. Any required flag that the build system needs, has to be
set in some other flag (which we will namespace with «MK_») so that the
build will use even if the user flags are passed, even though the user
should be able to override by appending after them. We pass CPPFLAGS to
any compilation command that missed them.

Signed-off-by: Guillem Jover <guillem@hadrons.org>

Gbp-Pq: Name 0011-build-Honour-user-build-flags.patch
---
 harness/Makefile |  9 ++++++---
 src/Makefile     | 18 +++++++++---------
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/harness/Makefile b/harness/Makefile
index c7ce5ec..bb2719f 100644
--- a/harness/Makefile
+++ b/harness/Makefile
@@ -6,13 +6,16 @@ PROGS:=$(PARTPROGS) $(EXTRAPROGS)
 HARNESS_SRCS:=main.c
 # io_queue.c
 
-CFLAGS+=-Wall -I../src -g -O2
+MK_CPPFLAGS = -I../src $(CPPFLAGS)
+CFLAGS ?= -Wall -g -O2
+MK_CFLAGS = $(CFLAGS)
 #-lpthread -lrt
+MK_LDFLAGS = main.c $(LIBAIO) -lpthread $(LDFLAGS)
 
 # gcc-11 does not like the test case in 3.t that
 # passes an invalid pointer (-1) to the kernel, so
 # tell the compiler we do not need a warning here
-cases/3.p:	CFLAGS+=-Wno-stringop-overflow
+cases/3.p:	MK_CFLAGS+=-Wno-stringop-overflow
 
 # Change this on the build line to run tests against the installed libraries:
 # make LIBAIO=-laio partcheck
@@ -21,7 +24,7 @@ LIBAIO?=../src/libaio.a
 all: $(PROGS)
 
 $(PROGS): %.p: %.t $(HARNESS_SRCS)
-	$(CC) $(CFLAGS) -DTEST_NAME=\"$<\" -o $@ main.c $(LIBAIO) -lpthread
+	$(CC) $(MK_CPPFLAGS) $(MK_CFLAGS) -DTEST_NAME=\"$<\" -o $@ $(MK_LDFLAGS)
 
 clean:
 	rm -f $(PROGS) *.o runtests.out rofile wofile rwfile
diff --git a/src/Makefile b/src/Makefile
index a53c43c..924b192 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -3,12 +3,12 @@ prefix=/usr
 includedir=$(prefix)/include
 libdir=$(prefix)/lib
 
-CFLAGS ?= -g -fomit-frame-pointer -O2
-CFLAGS += -Wall -I. -fPIC
-SO_CFLAGS=-shared $(CFLAGS)
-L_CFLAGS=$(CFLAGS)
-LINK_FLAGS=
-LINK_FLAGS+=$(LDFLAGS)
+MK_CPPFLAGS = -I. $(CPPFLAGS)
+CFLAGS ?= -Wall -g -fomit-frame-pointer -O2
+MK_CFLAGS = -fPIC $(CFLAGS)
+SO_CFLAGS = -shared $(MK_CFLAGS)
+L_CFLAGS = $(MK_CFLAGS)
+MK_LDFLAGS = $(LDFLAGS)
 ENABLE_SHARED ?= 1
 
 soname=libaio.so.1
@@ -43,10 +43,10 @@ libaio_sobjs := $(patsubst %.c,%.os,$(libaio_srcs))
 $(libaio_objs) $(libaio_sobjs): libaio.h vsys_def.h
 
 %.os: %.c
-	$(CC) $(SO_CFLAGS) -c -o $@ $<
+	$(CC) $(MK_CPPFLAGS) $(SO_CFLAGS) -c -o $@ $<
 
 %.ol: %.c
-	$(CC) $(L_CFLAGS) -c -o $@ $<
+	$(CC) $(MK_CPPFLAGS) $(L_CFLAGS) -c -o $@ $<
 
 AR ?= ar
 RANLIB ?= ranlib
@@ -56,7 +56,7 @@ libaio.a: $(libaio_objs)
 	$(RANLIB) libaio.a
 
 $(libname): $(libaio_sobjs) libaio.map
-	$(CC) $(SO_CFLAGS) -Wl,--version-script=libaio.map -Wl,-soname=$(soname) -o $@ $(libaio_sobjs) $(LINK_FLAGS)
+	$(CC) $(SO_CFLAGS) -Wl,--version-script=libaio.map -Wl,-soname=$(soname) -o $@ $(libaio_sobjs) $(MK_LDFLAGS)
 
 install: $(all_targets)
 	install -D -m 644 libaio.h $(DESTDIR)$(includedir)/libaio.h
-- 
2.30.2