[xen stable-4.16] build: fix exported variable name CFLAGS_stack_boundary

[patchbot@xxxxxxx]

commit 17093dbac91d187607ceb30b9e2b177fd7b38559
Author:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
AuthorDate: Wed Feb 16 15:53:04 2022 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Feb 16 15:53:04 2022 +0100

    build: fix exported variable name CFLAGS_stack_boundary
    
    Exporting a variable with a dash doesn't work reliably, they may be
    striped from the environment when calling a sub-make or sub-shell.
    
    CFLAGS-stack-boundary start to be removed from env in patch "build:
    set ALL_OBJS in main Makefile; move prelink.o to main Makefile" when
    running `make "ALL_OBJS=.."` due to the addition of the quote. At
    least in my empirical tests.
    
    Fixes: 2740d96efd ("xen/build: have the root Makefile generates the CFLAGS")
    Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/Rules.mk     | 4 ++--
 xen/arch/x86/arch.mk      | 4 ++--
 xen/arch/x86/efi/Makefile | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/Rules.mk b/xen/arch/x86/Rules.mk
index 56fe22c979..7aef93f5f3 100644
--- a/xen/arch/x86/Rules.mk
+++ b/xen/arch/x86/Rules.mk
@@ -6,5 +6,5 @@ object_label_flags = '-D__OBJECT_LABEL__=$(subst 
$(BASEDIR)/,,$(CURDIR))/$@'
 else
 object_label_flags = '-D__OBJECT_LABEL__=$(subst /,$$,$(subst -,_,$(subst 
$(BASEDIR)/,,$(CURDIR))/$@))'
 endif
-c_flags += $(object_label_flags) $(CFLAGS-stack-boundary)
-a_flags += $(object_label_flags) $(CFLAGS-stack-boundary)
+c_flags += $(object_label_flags) $(CFLAGS_stack_boundary)
+a_flags += $(object_label_flags) $(CFLAGS_stack_boundary)
diff --git a/xen/arch/x86/arch.mk b/xen/arch/x86/arch.mk
index ce0c1a0e7f..1109595fbc 100644
--- a/xen/arch/x86/arch.mk
+++ b/xen/arch/x86/arch.mk
@@ -48,8 +48,8 @@ CFLAGS-$(CONFIG_INDIRECT_THUNK) += -fno-jump-tables
 
 # If supported by the compiler, reduce stack alignment to 8 bytes. But allow
 # this to be overridden elsewhere.
-$(call cc-option-add,CFLAGS-stack-boundary,CC,-mpreferred-stack-boundary=3)
-export CFLAGS-stack-boundary
+$(call cc-option-add,CFLAGS_stack_boundary,CC,-mpreferred-stack-boundary=3)
+export CFLAGS_stack_boundary
 
 ifeq ($(CONFIG_UBSAN),y)
 # Don't enable alignment sanitisation.  x86 has efficient unaligned accesses,
diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile
index 87b927ed86..abae493bf3 100644
--- a/xen/arch/x86/efi/Makefile
+++ b/xen/arch/x86/efi/Makefile
@@ -12,7 +12,7 @@ EFIOBJ-y := boot.init.o pe.init.o ebmalloc.o runtime.o
 EFIOBJ-$(CONFIG_COMPAT) += compat.o
 
 $(call cc-option-add,cflags-stack-boundary,CC,-mpreferred-stack-boundary=4)
-$(EFIOBJ-y): CFLAGS-stack-boundary := $(cflags-stack-boundary)
+$(EFIOBJ-y): CFLAGS_stack_boundary := $(cflags-stack-boundary)
 
 obj-y := stub.o
 obj-$(XEN_BUILD_EFI) := $(filter-out %.init.o,$(EFIOBJ-y))
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16