--- giflib-4.2.3.ebuild
+++ giflib-4.2.3.ebuild
@@ -28,6 +28,7 @@
 	sed -i '/^SUBDIRS/s/doc//' Makefile.am || die
 
 	epatch "${FILESDIR}"/${PN}-4.1.6-giffix-null-Extension-fix.patch
+	sed -e "s/AM_CONFIG_HEADER/AC_CONFIG_HEADERS/" -i configure.ac
 	eautoreconf
 }