Use -isystem for linux-headers dir

glibc and Linux-provided headers are known to generate macro
redefinition warnings when used together.  For example:
<linux/mman.h> and <sys/mman.h> duplicate some macro definitions.

We normally never see those warnings because GCC suppresses
warnings generated by system headers.  We carry our own copy of
Linux header files, though, and this makes those warnings not be
suppressed when glibc headers are included before Linux headers
(e.g. if <sys/mman.h> is included before <linux/mman.h>).

Use -isystem instead of -I for linux-headers.  This makes the
compiler treat our linux-headers directory the same way it treats
system-provided Linux headers, and suppress warnings generated by
them.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Eduardo Habkost 2020-03-11 19:23:41 -04:00 committed by Paolo Bonzini
parent 3df261b667
commit 67cf3f5cf5
2 changed files with 2 additions and 2 deletions

View file

@ -12,7 +12,7 @@ endif
$(call set-vpath, $(SRC_PATH):$(BUILD_DIR))
ifdef CONFIG_LINUX
QEMU_CFLAGS += -I../linux-headers
QEMU_CFLAGS += -isystem ../linux-headers
endif
QEMU_CFLAGS += -iquote .. -iquote $(SRC_PATH)/target/$(TARGET_BASE_ARCH) -DNEED_CPU_H

2
configure vendored
View file

@ -900,7 +900,7 @@ Linux)
linux="yes"
linux_user="yes"
kvm="yes"
QEMU_INCLUDES="-I\$(SRC_PATH)/linux-headers -I$PWD/linux-headers $QEMU_INCLUDES"
QEMU_INCLUDES="-isystem \$(SRC_PATH)/linux-headers -isystem $PWD/linux-headers $QEMU_INCLUDES"
supported_os="yes"
libudev="yes"
;;