https://bugs.gentoo.org/876911
https://bugs.gentoo.org/299940
--- a/http-fetcher.m4
+++ b/http-fetcher.m4
@@ -10,7 +10,7 @@ dnl  understanding is that this should only be done if necessary.
 dnl  The macro also adds the appropriate -L and -I values to CFLAGS so that
 dnl  headers are found and libraries are linked.
 dnl
-AC_DEFUN(AC_PATH_HFETCHER,
+AC_DEFUN([AC_PATH_HFETCHER],
 [dnl
 
 darwin=no;