Add GMP initialization

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/util/gmp_init.cpp

@@ -0,0 +1,39 @@
+/*
+Copyright (c) 2013 Microsoft Corporation. All rights reserved. 
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura 
+*/
+#include <new>
+#include <gmp.h>
+#include <cstdlib>
+
+extern "C" void * cxx_malloc(size_t size) {
+    void * p = malloc(size);
+    if (p != 0 || size == 0)
+        return p;
+    
+    throw std::bad_alloc();
+}
+
+extern "C" void * cxx_realloc(void * q, size_t, size_t new_size) {
+    void* p = realloc(q, new_size);
+    if (p != 0 || new_size == 0)
+        return p;
+    
+    throw std::bad_alloc();
+}
+
+extern "C" void cxx_free(void * p, size_t) {
+    free(p);
+}
+
+class gmp_init {
+public:
+    gmp_init() {
+        mp_set_memory_functions(cxx_malloc, cxx_realloc, cxx_free);
+    }
+};
+
+gmp_init g_gmp_init;
+