Revert "Remove gmp from AOS"

This reverts commit f37c97684f0910a3f241394549392f00145ab0f7.

We need gmp for SymEngine for symbolicmanipultion in C++

Change-Id: Ia13216d1715cf96944f7b4f422b7a799f921d4a4
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/third_party/gmp/mp_set_fns.c b/third_party/gmp/mp_set_fns.c
new file mode 100644
index 0000000..b7bcd5b
--- /dev/null
+++ b/third_party/gmp/mp_set_fns.c
@@ -0,0 +1,49 @@
+/* mp_set_memory_functions -- Set the allocate, reallocate, and free functions
+   for use by the mp package.
+
+Copyright 1991, 1993, 1994, 2000, 2001 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of either:
+
+  * the GNU Lesser General Public License as published by the Free
+    Software Foundation; either version 3 of the License, or (at your
+    option) any later version.
+
+or
+
+  * the GNU General Public License as published by the Free Software
+    Foundation; either version 2 of the License, or (at your option) any
+    later version.
+
+or both in parallel, as here.
+
+The GNU MP Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library.  If not,
+see https://www.gnu.org/licenses/.  */
+
+#include "gmp-impl.h"
+
+void
+mp_set_memory_functions (void *(*alloc_func) (size_t),
+			 void *(*realloc_func) (void *, size_t, size_t),
+			 void (*free_func) (void *, size_t)) __GMP_NOTHROW
+{
+  if (alloc_func == 0)
+    alloc_func = __gmp_default_allocate;
+  if (realloc_func == 0)
+    realloc_func = __gmp_default_reallocate;
+  if (free_func == 0)
+    free_func = __gmp_default_free;
+
+  __gmp_allocate_func = alloc_func;
+  __gmp_reallocate_func = realloc_func;
+  __gmp_free_func = free_func;
+}