[xen staging-4.20] CI: consistently use DOCKER_CMD in makefiles

[patchbot@xxxxxxx]

commit 23f7c8341c48fa6db9ce8c0be41738a508cf1642
Author:     Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
AuthorDate: Mon Apr 7 14:31:06 2025 +0200
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed May 7 15:28:02 2025 +0100

    CI: consistently use DOCKER_CMD in makefiles
    
    This allows rebuilding containers using podman too.
    
    Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    (cherry picked from commit 5606b982acd44cc1f0715c424a11b2e76420aa18)
---
 automation/build/Makefile           | 4 ++--
 automation/tests-artifacts/Makefile | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/automation/build/Makefile b/automation/build/Makefile
index 4df43b0407..fedf7524da 100644
--- a/automation/build/Makefile
+++ b/automation/build/Makefile
@@ -31,8 +31,8 @@ clean:
 define CLEAN_RULE
 .PHONY: clean-$(1)
 clean-$(1):
-       if [ -n "$$$$(docker image ls -q $(REGISTRY)/$(subst /,:,$(1)))" ]; 
then \
-               docker image rm $(REGISTRY)/$(subst /,:,$(1)); \
+       if [ -n "$$$$($(DOCKER_CMD) image ls -q $(REGISTRY)/$(subst /,:,$(1)))" 
]; then \
+               $(DOCKER_CMD) image rm $(REGISTRY)/$(subst /,:,$(1)); \
        fi
 
 endef
diff --git a/automation/tests-artifacts/Makefile 
b/automation/tests-artifacts/Makefile
index d055cd696b..80a60a94f3 100644
--- a/automation/tests-artifacts/Makefile
+++ b/automation/tests-artifacts/Makefile
@@ -10,9 +10,9 @@ help:
        @echo "To push container builds, set the env var PUSH"
 
 %: %.dockerfile ## Builds containers
-       docker build --pull -t $(REGISTRY)/$(@D):$(@F) -f $< $(<D)
+       $(DOCKER_CMD) build --pull -t $(REGISTRY)/$(@D):$(@F) -f $< $(<D)
        @if [ ! -z $${PUSH+x} ]; then \
-               docker push $(REGISTRY)/$(@D):$(@F); \
+               $(DOCKER_CMD) push $(REGISTRY)/$(@D):$(@F); \
        fi
 
 .PHONY: all
--
generated by git-patchbot for /home/xen/git/xen.git#staging-4.20