diff --git a/configure.ac b/configure.ac
index 8d2fdfc..85ca8d4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -14,7 +14,7 @@ dnl from the use of this software.
 AC_PREREQ([2.68])
 AC_INIT([pkgconf], [1.9.90], [https://todo.sr.ht/~kaniini/pkgconf])
 AC_CONFIG_SRCDIR([cli/main.c])
-AC_CONFIG_MACRO_DIRS([m4])
+AC_CONFIG_MACRO_DIR([m4])
 AX_CHECK_COMPILE_FLAG([-Wall], [CFLAGS="$CFLAGS -Wall"])
 AX_CHECK_COMPILE_FLAG([-Wextra], [CFLAGS="$CFLAGS -Wextra"])
 AX_CHECK_COMPILE_FLAG([-Wformat=2], [CFLAGS="$CFLAGS -Wformat=2"])