diff --git a/make/autoconf.mk b/make/autoconf.mk
index 2a078831..17cb5766 100644
--- a/make/autoconf.mk
+++ b/make/autoconf.mk
@@ -8,7 +8,7 @@ DISTCLEAN += configure config.log autoscan.log configure.ac config.status
 AC_FILES_IN = $(shell find . -maxdepth 2 -name '*.in' | grep -ve "contrib\|dist\|nomake")
 AC_FILES    = $(basename $(AC_FILES_IN))
 CAT ?= /bin/cat
-SED ?= /usr/bin/sed
+SED ?= $(firstword $(wildcard /usr/bin/sed /bin/sed))
 
 all: config.acdone make_all
 config: config.acdone $(AC_FILES)