gentoo-overlay/dev-libs/hidapi/files/hidapi-0.8.0_rc1_p20140719-autoconf-2.70.patch

https://bugs.gentoo.org/750983
--- a/configure.ac
+++ b/configure.ac
@@ -20,7 +20,6 @@ LTLDFLAGS="-version-info ${lt_current}:${lt_revision}:${lt_age}"
 
 AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE([foreign -Wall -Werror])
-AC_CONFIG_MACRO_DIR([m4])
 
 m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
 LT_INIT