linux4.9: patch Makefile to add -Wno-error

Try to work around the gcc-9.1.0 warning on armv7l*

Signed-off-by: Jürgen Buchmüller <pullmoll@t-online.de>

srcpkgs/linux4.9/template

@@ -35,8 +35,6 @@ mutable_files="
  /usr/lib/modules/${_kernver}/modules.alias.bin
  /usr/lib/modules/${_kernver}/modules.devname"
 
-CFLAGS="-Wno-missing-attributes"
-
 do_configure() {
 	# If there's a file called <arch>-dotconfig, use it to
 	# configure the kernel; otherwise use arch defaults and all stuff
@@ -87,6 +85,7 @@ do_build() {
 	fi
 	export LDFLAGS=
 	make ARCH=$arch ${_version} ${_cross} ${makejobs} prepare
+	vsed -i Makefile -e "/KBUILD_CFLAGS *:=/s/:= /:= -Wno-error /"
 	make ARCH=$arch ${_version} ${_cross} ${makejobs} ${_args}
 }
 do_install() {