diff --git a/Makefile.inc1 b/Makefile.inc1
index 4f0aabaad487..dcebc1814f08 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -19,6 +19,7 @@
 #	    list
 #	TARGET="machine" to crossbuild world for a different machine type
 #	TARGET_ARCH= may be required when a TARGET supports multiple endians
+#	BUILDENV_SHELL= shell to launch for the buildenv target (def:/bin/sh)
 
 #
 # The intended user-driven targets are:
@@ -108,6 +109,8 @@ CLEANDIR=	cleandir
 
 LOCAL_TOOL_DIRS?=
 
+BUILDENV_SHELL?=/bin/sh
+
 CVS?=		cvs
 CVSFLAGS?=	-A -P -d -I!
 SVN?=		svn
@@ -558,7 +561,7 @@ buildenvvars:
 
 buildenv:
 	@echo Entering world for ${TARGET_ARCH}:${TARGET}
-	@cd ${.CURDIR} && env ${WMAKEENV} sh || true
+	@cd ${.CURDIR} && env ${WMAKEENV} ${BUILDENV_SHELL} || true
 
 TOOLCHAIN_TGTS=	${WMAKE_TGTS:N_depend:Neverything:Nbuild32}
 toolchain: ${TOOLCHAIN_TGTS}