diff --git a/configure.ac b/configure.ac
index ed550fa..4f8c7a4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -15,7 +15,7 @@ AC_PREREQ([2.68])
 AC_INIT([pkgconf], [1.1.90], [http://github.com/pkgconf/pkgconf/issues])
 AC_CONFIG_SRCDIR([main.c])
 AC_CONFIG_HEADERS([libpkgconf/config.h])
-AC_CHECK_FUNCS([strlcpy strlcat strndup cygwin_conv_path])
+AC_CHECK_FUNCS([strlcpy strlcat strndup realpath cygwin_conv_path])
 AC_CHECK_HEADERS([sys/stat.h])
 AM_INIT_AUTOMAKE([foreign no-dist-gzip dist-xz subdir-objects])
 AM_SILENT_RULES([yes])