Fix newvers.sh with BUILD_WITH_STRICT_TMPPATH=1

newvers.sh runs mkfifo which did not exist before this change.
However, I didn't notice before because it is run from a function
where a missing command does cause a noticeable failure.

Reviewed By:	emaste, markj
Differential Revision: https://reviews.freebsd.org/D18377

Makefile.inc1

@@ -2215,6 +2215,8 @@ _basic_bootstrap_tools+=usr.bin/ldd
 _basic_bootstrap_tools+=usr.sbin/services_mkdb usr.sbin/pwd_mkdb
 # sysctl/chflags are required for installkernel:
 _basic_bootstrap_tools+=sbin/sysctl bin/chflags
+# mkfifo is used by sys/conf/newvers.sh
+_basic_bootstrap_tools+=usr.bin/mkfifo
 
 .if ${MK_AMD} != "no"
 # unifdef is only used by usr.sbin/amd/libamu/Makefile

sys/conf/newvers.sh

@@ -86,7 +86,7 @@ git_tree_modified()
 	local fifo
 
 	fifo=$(mktemp -u)
-	mkfifo -m 600 $fifo
+	mkfifo -m 600 $fifo || exit 1
 	$git_cmd --work-tree=${VCSTOP} diff-index HEAD > $fifo &
 	while read smode dmode ssha dsha status file; do
 		if ! expr $dsha : '^00*$' >/dev/null; then