Index: head/Makefile.inc1
===================================================================
--- head/Makefile.inc1
+++ head/Makefile.inc1
@@ -262,10 +262,11 @@
 SUBDIR+=contrib/ofed
 .endif
 
-# Local directories are last, since it is nice to at least get the base
-# system rebuilt before you do them.
+# Local directories are built in parallel with the base system directories.
+# Users may insert a .WAIT directive at the beginning or elsewhere within
+# the LOCAL_DIRS and LOCAL_LIB_DIRS lists as needed.
 .for _DIR in ${LOCAL_DIRS}
-.if exists(${.CURDIR}/${_DIR}/Makefile)
+.if ${_DIR} == ".WAIT" || exists(${.CURDIR}/${_DIR}/Makefile)
 SUBDIR+=	${_DIR}
 .endif
 .endfor
@@ -276,7 +277,7 @@
 _REDUNDANT_LIB_DIRS+=    ${LOCAL_LIB_DIRS:M${_DIR}*}
 .endfor
 .for _DIR in ${LOCAL_LIB_DIRS}
-.if empty(_REDUNDANT_LIB_DIRS:M${_DIR}) && exists(${.CURDIR}/${_DIR}/Makefile)
+.if ${_DIR} == ".WAIT" || (empty(_REDUNDANT_LIB_DIRS:M${_DIR}) && exists(${.CURDIR}/${_DIR}/Makefile))
 SUBDIR+=	${_DIR}
 .endif
 .endfor
@@ -2445,7 +2446,7 @@
 _generic_libs+=	sbin/ipf/libipf
 .endif
 .for _DIR in ${LOCAL_LIB_DIRS}
-.if exists(${.CURDIR}/${_DIR}/Makefile) && empty(_generic_libs:M${_DIR})
+.if ${_DIR} == ".WAIT"  || (empty(_generic_libs:M${_DIR}) && exists(${.CURDIR}/${_DIR}/Makefile))
 _generic_libs+= ${_DIR}
 .endif
 .endfor
Index: head/share/man/man7/build.7
===================================================================
--- head/share/man/man7/build.7
+++ head/share/man/man7/build.7
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 3, 2017
+.Dd December 24, 2017
 .Dt BUILD 7
 .Os
 .Sh NAME
@@ -509,6 +509,15 @@
 the root of the source tree to build as part of the
 .Cm everything
 target.
+The directories are built in parallel with each other,
+and with the base system directories.
+Insert a
+.Va .WAIT
+directive at the beginning of the
+.Va LOCAL_DIRS
+list to ensure all base system directories are built first.
+.Va .WAIT
+may also be used as needed elsewhere within the list.
 .It Va LOCAL_ITOOLS
 If set, this variable supplies a list of additional tools that are used by the
 .Cm installworld
@@ -520,6 +529,15 @@
 the root of the source tree to build as part of the
 .Cm libraries
 target.
+The directories are built in parallel with each other,
+and with the base system libraries.
+Insert a
+.Va .WAIT
+directive at the beginning of the
+.Va LOCAL_DIRS
+list to ensure all base system libraries are built first.
+.Va .WAIT
+may also be used as needed elsewhere within the list.
 .It Va LOCAL_MTREE
 If set, this variable supplies a list of additional mtrees relative to the
 root of the source tree to use as part of the