diff --git a/configure.ac b/configure.ac
index 335b0c5..806b9e4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -31,7 +31,13 @@ AC_PROG_INSTALL
 AC_PATH_PROG(BDFTOPCF, bdftopcf)
 AC_PATH_PROG(UCS2ANY, ucs2any)
 AC_PATH_PROG(MKFONTSCALE, mkfontscale)
+if test x"$MKFONTSCALE" = x; then
+	AC_MSG_ERROR([mkfontscale is required to build adobe-75dpi fonts.])
+fi
 AC_PATH_PROG(MKFONTDIR, mkfontdir)
+if test x"$MKFONTDIR" = x; then
+	AC_MSG_ERROR([mkfontdir is required to build adobe-75dpi fonts.])
+fi
 
 m4_ifdef([AS_HELP_STRING], , [m4_define([AS_HELP_STRING], m4_defn([AC_HELP_STRING]))])