diff --git a/bootstrap b/bootstrap
index 97300b4..8afbd8e 100755
--- a/bootstrap
+++ b/bootstrap
@@ -733,7 +733,7 @@ find "$m4_base" "$source_base" \
 # Reconfigure, getting other files.
 
 # Skip autoheader if it's not needed.
-grep '^[	 ]*AC_CONFIG_HEADERS\>' configure.ac >/dev/null ||
+grep -E '^[	 ]*AC_CONFIG_HEADERS?\>' configure.ac >/dev/null ||
   AUTOHEADER=true
 
 for command in \