From: Changqing Li Date: Wed, 23 Nov 2022 08:23:46 +0800 Subject: [Linuxptp-devel] [PATCH] makefile: use conditional assignment for KBUILD_OUTPUT Refer [1],from make 4.4, all variables that are marked as export will also be passed to the shell started by the shell function. use "=" will make KBUILD_OUTPUT always empty for shell function, use "?=" to make "export KBUILD_OUTPUT" in enrironment can work. [snip of 4.4 NEWS] * WARNING: Backward-incompatibility! Previously makefile variables marked as export were not exported to commands started by the $(shell ...) function. Now, all exported variables are exported to $(shell ...). [snip] [1] https://git.savannah.gnu.org/cgit/make.git/tree/NEWS?h=4.4&id=ed493f6c9116cc217b99c2cfa6a95f15803235a2#n74 Signed-off-by: Changqing Li [Retrieved from mailing list. The patch was not yet accepted and applied: https://www.mail-archive.com/linuxptp-devel@lists.sourceforge.net/msg06151.html] Signed-off-by: Heiko Thiery --- makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/makefile b/makefile index 9aed383..ba3fb38 100644 --- a/makefile +++ b/makefile @@ -15,7 +15,7 @@ # with this program; if not, write to the Free Software Foundation, Inc., # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. -KBUILD_OUTPUT = +KBUILD_OUTPUT ?= DEBUG = CC = $(CROSS_COMPILE)gcc -- 2.25.1