Create sys/boot/libsa and build libstand.a there

Build libstand from inside the sys/boot build. Redirect all users in
sys/boot to grab it from there. We still build it as libstand.a for
the moment. When lib/libstand is moved here, we'll change the name.

Sponsored by: Netflix

sys/boot/Makefile

@@ -2,6 +2,7 @@
 
 .include <src.opts.mk>
 
+SUBDIR+=		libsa
 .if ${MK_FORTH} != "no"
 # Build the add-in FORTH interpreter.
 SUBDIR+=		ficl

sys/boot/Makefile.inc

@@ -7,7 +7,7 @@ __BOOT_MAKEFILE_INC__=${MFILE}
 
 SASRC=${SRCTOP}/lib/libstand
 # Normal stand alone library
-LIBSA=${OBJTOP}/lib/libstand/libstand.a
+LIBSA=${OBJTOP}/sys/boot/libsa/libstand.a
 # stand alone library compiled for 32-bit version of the processor
 LIBSA32=${OBJTOP}/sys/boot/libstand32/libstand.a
 # stand along library compiled for userboot

sys/boot/libsa/Makefile

@@ -0,0 +1,14 @@
+# $FreeBSD$
+
+.include <src.opts.mk>
+
+.include "../Makefile.inc"
+
+LIBSTAND_SRC=	${SASRC}
+LIBC_SRC=	${SRCTOP}/lib/libc
+INTERNALLIB=
+INCS=
+MAN=
+.PATH:	${SASRC}
+
+.include "${SASRC}/Makefile"