Cleanup CFALGS usage here

Only define the CFLAGS we need.
SSP_CFLAGS is now defined globally, no need to define it here.
Define -D_STANDALONE globally for src/stand builds.

Sponsored by: Netflix

stand/defs.mk

@@ -39,7 +39,7 @@ LIBSA32=	${BOOTOBJ}/libsa32/libsa32.a
 .endif
 
 # Standard options:
-CFLAGS+=	-I${SASRC}
+CFLAGS+=	-I${SASRC} -D_STANDALONE
 CFLAGS+=	-I${SYSDIR}
 
 # Filesystem support

stand/powerpc/boot1.chrp/Makefile

@@ -2,8 +2,6 @@
 
 .include <bsd.init.mk>
 
-SSP_CFLAGS=
-
 PROG=           boot1.elf
 NEWVERSWHAT=    "Open Firmware boot block" ${MACHINE_ARCH}
 INSTALLFLAGS=   -b
@@ -13,7 +11,7 @@ SRCS=		boot1.c ashldi3.c syncicache.c
 
 MAN=
 
-CFLAGS= -I${LDRSRC} -I${SYSDIR} -I${SASRC} -D_STANDALONE
+CFLAGS+=-I${LDRSRC}
 LDFLAGS=-nostdlib -static -Wl,-N
 
 .PATH:  ${SYSDIR}/libkern ${SRCTOP}/lib/libc/powerpc/gen ${.CURDIR}