---
 sigscheme/Makefile.am            |    2 ++
 sigscheme/libgcroots/Makefile.am |    2 ++
 2 files changed, 4 insertions(+)

--- a/sigscheme/Makefile.am
+++ b/sigscheme/Makefile.am
@@ -4,6 +4,8 @@
 endif
 SUBDIRS += include src lib test test-c bench
 
+ACLOCAL_AMFLAGS = -I m4
+
 # To make 'make distclean' workable on --with-libgcroots=tiny-subdir,
 # libgcroots must be eliminated from $DIST_SUBDIRS.
 DIST_SUBDIRS = $(SUBDIRS)
--- a/sigscheme/libgcroots/Makefile.am
+++ b/sigscheme/libgcroots/Makefile.am
@@ -19,6 +19,8 @@
 
 include libtool-version.mk
 
+ACLOCAL_AMFLAGS = -I m4
+
 # $(distdir) does work as a part of $(RELEASE_URL) when configured as a
 # subpackage.
 DIST_NAME = $(PACKAGE)-$(VERSION)