make: Provide mandatory options in cflags-y variable

In case if CFLAGS is overriden from command line we don't
see our headers anymore. So provide mandatory options in
ccflags-y variable to fix that.

https://bugzilla.openvz.org/show_bug.cgi?id=2521Reported-by: Jan Engelhardt <jengelh@inai.de>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Tested-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Makefile

@@ -76,8 +76,10 @@ ARCH_DIR	:= arch/$(ARCH)
 
 $(if $(wildcard $(ARCH_DIR)),,$(error "The architecture $(ARCH) isn't supported"))
 
-CFLAGS		+= -iquote include -iquote pie -iquote . -iquote $(ARCH_DIR)
-CFLAGS		+= -iquote $(ARCH_DIR)/include -fno-strict-aliasing
+cflags-y		+= -iquote include -iquote pie -iquote .
+cflags-y		+= -iquote $(ARCH_DIR) -iquote $(ARCH_DIR)/include
+cflags-y		+= -fno-strict-aliasing
+export cflags-y
 
 LIBS		:= -lrt -lpthread -lprotobuf-c
 
@@ -103,6 +105,7 @@ ARCH-LIB	:= arch/$(ARCH)/crtools.built-in.o
 
 export E Q CC ECHO MAKE CFLAGS LIBS ARCH DEFINES MAKEFLAGS
 export SRC_DIR SYSCALL-LIB SH RM ARCH_DIR OBJCOPY LDARCH LD
+export cflags-y
 
 include scripts/Makefile.version
 include scripts/Makefile.rules

pie/Makefile

@@ -12,7 +12,7 @@ restorer-obj-y		+= restorer.o
 restorer-obj-e		+= $(ARCH_DIR)/restorer.o
 restorer-libs-e		+= $(SYSCALL-LIB)
 
-CFLAGS			+= -fpie  -Wa,--noexecstack -fno-strict-aliasing
+cflags-y		+= -fpie  -Wa,--noexecstack -fno-strict-aliasing
 ASMFLAGS		+= -D__ASSEMBLY__
 
 GEN-OFFSETS		:= gen-offsets.sh

scripts/Makefile.rules

@@ -5,43 +5,43 @@
 define gen-rule-o-from-c-by-name
 $(1).o: $(1).c
 	$$(E) "  CC      " $$@
-	$$(Q) $$(CC) -c $$(CFLAGS) $(2) $$< -o $$@
+	$$(Q) $$(CC) -c $$(CFLAGS) $$(cflags-y) $(2) $$< -o $$@
 endef
 
 define gen-rule-i-from-c-by-name
 $(1).i: $(1).c
 	$$(E) "  CC      " $$@
-	$$(Q) $$(CC) -E $$(CFLAGS) $(2) $$< -o $$@
+	$$(Q) $$(CC) -E $$(CFLAGS) $$(cflags-y) $(2) $$< -o $$@
 endef
 
 define gen-rule-s-from-c-by-name
 $(1).s: $(1).c
 	$$(E) "  CC      " $$@
-	$$(Q) $$(CC) -S $$(CFLAGS) $(2) -fverbose-asm $$< -o $$@
+	$$(Q) $$(CC) -S $$(CFLAGS) $$(cflags-y) $(2) -fverbose-asm $$< -o $$@
 endef
 
 define gen-rule-o-from-S-by-name
 $(1).o: $(1).S
 	$$(E) "  CC      " $$@
-	$$(Q) $$(CC) -c $$(CFLAGS) $(2) $$(ASMFLAGS) $(3) $$< -o $$@
+	$$(Q) $$(CC) -c $$(CFLAGS) $$(cflags-y) $(2) $$(ASMFLAGS) $(3) $$< -o $$@
 endef
 
 define gen-rule-d-from-c-by-name
 $(1).d: $(1).c
 	$$(E) "  DEP     " $$@
-	$$(Q) $$(CC) -M -MT $$@ -MT $$(patsubst %.d,%.o,$$@) $$(CFLAGS) $(2) $$< -o $$@
+	$$(Q) $$(CC) -M -MT $$@ -MT $$(patsubst %.d,%.o,$$@) $$(CFLAGS) $$(cflags-y) $(2) $$< -o $$@
 endef
 
 define gen-rule-d-from-S-by-name
 $(1).d: $(1).S
 	$$(E) "  DEP     " $$@
-	$$(Q) $$(CC) -M -MT $$@ -MT $$(patsubst %.d,%.o,$$@) $$(CFLAGS) $(2) $$< -o $$@
+	$$(Q) $$(CC) -M -MT $$@ -MT $$(patsubst %.d,%.o,$$@) $$(CFLAGS) $$(cflags-y) $(2) $$< -o $$@
 endef
 
 define gen-rule-i-from-S-by-name
 $(1).i: $(1).S
 	$$(E) "  CC      " $$@
-	$$(Q) $$(CC) -E $$(CFLAGS) $(2) $$< -o $$@
+	$$(Q) $$(CC) -E $$(CFLAGS) $$(cflags-y) $(2) $$< -o $$@
 endef
 
 ##