[Buildroot] [PATCH 2/2] package/qemu: filter out long make options

[Alexey Neyman]

Since qemu started using ninja, they have the following fragment in the
Makefile:

MAKE.n = $(findstring n,$(firstword $(MAKEFLAGS)))
NINJAFLAGS = ... $(if $(MAKE.n), -n) ...

Buildroot's generated makefile in the O= directory invokes make in the
base buildroot with --no-print-directory. However, make's placement of
the --no-print-directory in MAKEFLAGS varies between the versions of
the host make; make 4.3 places that at the end while make 3.82 places
it at the beginning. As a result, if building on a system with an older
host make, qemu's makefile invokes `ninja -n` which does not generate
any outputs.

To reproduce, on a CentOS 7 machine or docker image:
  mkdir /tmp/br-build && cd /tmp/br-build
  make -C ~/buildroot pc_x86_64_bios_defconfig O=`pwd`
  make menuconfig # Switch to glibc, enable "QEMU" and "QEMU tools"
  make all # Build succeeds
  find target -name qemu-img # No binary has been built

Signed-off-by: Alexey Neyman <stilor at att.net>
---
 package/qemu/qemu.mk | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/package/qemu/qemu.mk b/package/qemu/qemu.mk
index 470c285f16..ee3e7c3676 100644
--- a/package/qemu/qemu.mk
+++ b/package/qemu/qemu.mk
@@ -206,14 +206,15 @@ define QEMU_CONFIGURE_CMDS
 			$(QEMU_OPTS)
 endef
 
+# QEMU Makefile incorrectly interprets long options to make
 define QEMU_BUILD_CMDS
 	unset TARGET_DIR; \
-	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D)
+	MAKEFLAGS="$(filter-out --%,$(MAKEFLAGS))" $(TARGET_MAKE_ENV) $(MAKE) -C $(@D)
 endef
 
 define QEMU_INSTALL_TARGET_CMDS
 	unset TARGET_DIR; \
-	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) $(QEMU_MAKE_ENV) DESTDIR=$(TARGET_DIR) install
+	MAKEFLAGS="$(filter-out --%,$(MAKEFLAGS))" $(TARGET_MAKE_ENV) $(MAKE) -C $(@D) $(QEMU_MAKE_ENV) DESTDIR=$(TARGET_DIR) install
 endef
 
 $(eval $(generic-package))
-- 
2.27.0