Move implementations from impl/*.h to *_impl.h

src/num_impl.h

@@ -0,0 +1,22 @@
+// Copyright (c) 2013 Pieter Wuille
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef _SECP256K1_NUM_IMPL_H_
+#define _SECP256K1_NUM_IMPL_H_
+
+#if defined HAVE_CONFIG_H
+#include "libsecp256k1-config.h"
+#endif
+
+#include "num.h"
+
+#if defined(USE_NUM_GMP)
+#include "num_gmp_impl.h"
+#elif defined(USE_NUM_OPENSSL)
+#include "num_openssl_impl.h"
+#else
+#error "Please select num implementation"
+#endif
+
+#endif