Put in a band-aid to get the pc98 bootstraps building, now clang is the

default compiler.  This has two parts:
- Make sys/boot/pc98/boot2 always build with gcc for now, until we can
  figure out a way to shrink it enough when building with clang.
- Since sys/boot/p98/cdboot uses .code16 directives, which are not yet
  supported by clang's integrated assembler, use -no-integrated-as,
  similar to sys/boot/i386/cdboot.

Reviewed by:	nyan
MFC after:	1 week

sys/boot/pc98/boot2/Makefile

@@ -3,7 +3,7 @@
 .include <bsd.own.mk>
 
 # XXX: clang can compile the boot code just fine, but boot2 gets too big
-CC:=${CC:C/^(.*\/)?clang$/gcc/1}
+CC:=		gcc
 
 FILES=		boot boot1 boot2
 

sys/boot/pc98/cdboot/Makefile

@@ -13,3 +13,7 @@ ORG=	0x0000
 LDFLAGS=-e start -Ttext ${ORG} -Wl,-N,-S,--oformat,binary
 
 .include <bsd.prog.mk>
+
+# XXX: clang integrated-as doesn't grok .codeNN directives yet
+CFLAGS.cdboot.S=	${CLANG_NO_IAS}
+CFLAGS+=		${CFLAGS.${.IMPSRC:T}}