oprofile doesn't want GNU-levels of automake strictness so tell it to be "foreign".

Upstream-Status: Pending
Signed-off-by: Ross Burton <ross.burton@intel.com>

diff --git a/configure.ac b/configure.ac
index 5740585..cf6c316 100644
--- a/configure.ac
+++ b/configure.ac
@@ -16 +16 @@ AC_CONFIG_SRCDIR([libop/op_config.h])
-AM_INIT_AUTOMAKE
+AM_INIT_AUTOMAKE([foreign])