build: Rename as-insn-check to as-option-add

as-insn-check mutates the passed-in flags.  Rename it to as-option-add, in
line with cc-option-add, and update all callers.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

Config.mk

@@ -163,11 +163,11 @@ as-insn = $(if $(shell echo 'void _(void) { asm volatile ( $(2) ); }' \
                        | $(filter-out -M% %.d -include %/include/xen/config.h,$(1)) \
                               -c -x c -o /dev/null - 2>&1),$(4),$(3))
 
-# as-insn-check: Add an option to compilation flags, but only if insn is
+# as-option-add: Add an option to compilation flags, but only if insn is
 #                supported by assembler.
-# Usage: $(call as-insn-check,CFLAGS,CC,"nop",-DHAVE_GAS_NOP)
-as-insn-check = $(eval $(call as-insn-check-closure,$(1),$(2),$(3),$(4)))
-define as-insn-check-closure
+# Usage: $(call as-option-add,CFLAGS,CC,"insn",option-yes)
+as-option-add = $(eval $(call as-option-add-closure,$(1),$(2),$(3),$(4)))
+define as-option-add-closure
     ifeq ($$(call as-insn,$$($(2)) $$($(1)),$(3),y,n),y)
         $(1) += $(4)
     endif

xen/arch/x86/Rules.mk

@@ -14,13 +14,13 @@ CFLAGS += -msoft-float
 
 $(call cc-options-add,CFLAGS,CC,$(EMBEDDED_EXTRA_CFLAGS))
 $(call cc-option-add,CFLAGS,CC,-Wnested-externs)
-$(call as-insn-check,CFLAGS,CC,"vmcall",-DHAVE_GAS_VMX)
-$(call as-insn-check,CFLAGS,CC,"crc32 %eax$$(comma)%eax",-DHAVE_GAS_SSE4_2)
-$(call as-insn-check,CFLAGS,CC,"invept (%rax)$$(comma)%rax",-DHAVE_GAS_EPT)
-$(call as-insn-check,CFLAGS,CC,"rdrand %eax",-DHAVE_GAS_RDRAND)
-$(call as-insn-check,CFLAGS,CC,"rdfsbase %rax",-DHAVE_GAS_FSGSBASE)
-$(call as-insn-check,CFLAGS,CC,"rdseed %eax",-DHAVE_GAS_RDSEED)
-$(call as-insn-check,CFLAGS,CC,".equ \"x\"$$(comma)1", \
+$(call as-option-add,CFLAGS,CC,"vmcall",-DHAVE_GAS_VMX)
+$(call as-option-add,CFLAGS,CC,"crc32 %eax$$(comma)%eax",-DHAVE_GAS_SSE4_2)
+$(call as-option-add,CFLAGS,CC,"invept (%rax)$$(comma)%rax",-DHAVE_GAS_EPT)
+$(call as-option-add,CFLAGS,CC,"rdrand %eax",-DHAVE_GAS_RDRAND)
+$(call as-option-add,CFLAGS,CC,"rdfsbase %rax",-DHAVE_GAS_FSGSBASE)
+$(call as-option-add,CFLAGS,CC,"rdseed %eax",-DHAVE_GAS_RDSEED)
+$(call as-option-add,CFLAGS,CC,".equ \"x\"$$(comma)1", \
                      -U__OBJECT_LABEL__ -DHAVE_GAS_QUOTED_SYM \
                      '-D__OBJECT_LABEL__=$(subst $(BASEDIR)/,,$(CURDIR))/$$@')