Move savecore build enable to MD section of Makefile, currently enabled

for i386 and alpha.  Although it builds on sparc64, it does not yet work.
A similar hack as what is used on the sparc64 MD macros can be used to
make ia64 build too, but there doesn't seem to be much point.

sbin/Makefile

@@ -71,7 +71,6 @@ SUBDIR=	adjkerntz \
 	route \
 	routed \
 	rtsol \
-	savecore \
 	shutdown \
 	slattach \
 	spppcontrol \
@@ -87,7 +86,8 @@ SUBDIR+=cxconfig \
 	kget \
 	mount_nwfs \
 	mount_smbfs \
-	nextboot
+	nextboot \
+	savecore
 .if ${MACHINE} == "pc98"
 SUBDIR+=fdisk_pc98
 .else
@@ -95,6 +95,10 @@ SUBDIR+=fdisk
 .endif
 .endif
 
+.if ${MACHINE_ARCH} == "alpha"
+SUBDIR+=savecore
+.endif
+
 .if ${MACHINE_ARCH} == "ia64"
 SUBDIR+=fdisk
 .endif