mk: single mk fragment for new libc

. allow commands to use it by setting NEED_NBSDLIBC
	. also add mkfiles to clean and cleandepend so they
	  don't break on missing new mkfiles

share/mk/Makefile

@@ -12,7 +12,8 @@ FILES=	bsd.dep.mk bsd.files.mk \
 
 # MINIX-specific files
 FILES+= minix.bootprog.mk minix.service.mk minix.ackdep.mk \
-	minix.ack.mk minix.gcc.mk minix.gcov.mk pkgsrchooks.mk
+	minix.ack.mk minix.gcc.mk minix.gcov.mk pkgsrchooks.mk \
+	minix.newlibc.mk
 
 FILESDIR=/usr/share/mk
 .endif

share/mk/minix.newlibc.mk

@@ -0,0 +1,5 @@
+# Force clang/gcc and using new libc
+# Requires NBSD_LIBC and clang/gcc (we default to using clang)
+NBSD_LIBC:= yes
+CC:=${CC:C/^cc/clang/}
+COMPILER_TYPE:= gnu