Merge branch 'make-cflags' of https://github.com/phlax/liburing

* 'make-cflags' of https://github.com/phlax/liburing:
  build: Pass env CFLAGS through to make

Author: axboe

configure

@@ -120,8 +120,9 @@ print_config() {
 }
 
 # Default CFLAGS
-CFLAGS="-D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -include config-host.h"
-BUILD_CFLAGS=""
+ENV_CFLAGS="${CFLAGS}"
+CFLAGS="${CFLAGS:+$CFLAGS }-D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -include config-host.h"
+BUILD_CFLAGS="${ENV_CFLAGS}"
 
 # Print configure header at the top of $config_host_h
 echo "/*" > $config_host_h
@@ -588,6 +589,7 @@ fi
 echo "CC=$cc" >> $config_host_mak
 print_config "CC" "$cc"
 echo "CXX=$cxx" >> $config_host_mak
+echo "BUILD_CFLAGS=$BUILD_CFLAGS" >> $config_host_mak
 print_config "CXX" "$cxx"
 
 # generate io_uring_version.h

src/Makefile

@@ -13,6 +13,7 @@ override CPPFLAGS += -D_GNU_SOURCE \
 CFLAGS ?= -O3 -Wall -Wextra -fno-stack-protector
 override CFLAGS += -Wno-unused-parameter \
 	-DLIBURING_INTERNAL \
+	$(BUILD_CFLAGS) \
 	$(LIBURING_CFLAGS)
 SO_CFLAGS=-fPIC $(CFLAGS)
 L_CFLAGS=$(CFLAGS)