Check for existence of mempcpy

If it doesn't exist, provide a definition based on memcpy.

Signed-off-by: Ulf Hermann <ulf.hermann@qt.io>
diff --git a/libebl/ChangeLog b/libebl/ChangeLog
index 0560c6a..719d08d 100644
--- a/libebl/ChangeLog
+++ b/libebl/ChangeLog
@@ -1,3 +1,8 @@
+2017-02-15  Ulf Hermann  <ulf.hermann@qt.io>
+
+	* eblmachineflagname.c: Include system.h.
+	* eblopenbackend.c: Likewise.
+
 2016-07-08  Mark Wielaard  <mjw@redhat.com>
 
 	* Makefile.am (gen_SOURCES): Remove eblstrtab.c.