Add libgmp 6.2.0 to third_party

Don't build it yet.  That will come in the next review.

Change-Id: Idf3266558165e5ab45f4a41c98cc8c838c8244d5
diff --git a/third_party/gmp/mpn/vax/elf.m4 b/third_party/gmp/mpn/vax/elf.m4
new file mode 100644
index 0000000..e04f0ba
--- /dev/null
+++ b/third_party/gmp/mpn/vax/elf.m4
@@ -0,0 +1,54 @@
+divert(-1)
+
+dnl  m4 macros for VAX assembler.
+
+dnl  Copyright 2001, 2012 Free Software Foundation, Inc.
+
+dnl  This file is part of the GNU MP Library.
+dnl
+dnl  The GNU MP Library is free software; you can redistribute it and/or modify
+dnl  it under the terms of either:
+dnl
+dnl    * the GNU Lesser General Public License as published by the Free
+dnl      Software Foundation; either version 3 of the License, or (at your
+dnl      option) any later version.
+dnl
+dnl  or
+dnl
+dnl    * the GNU General Public License as published by the Free Software
+dnl      Foundation; either version 2 of the License, or (at your option) any
+dnl      later version.
+dnl
+dnl  or both in parallel, as here.
+dnl
+dnl  The GNU MP Library is distributed in the hope that it will be useful, but
+dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+dnl  for more details.
+dnl
+dnl  You should have received copies of the GNU General Public License and the
+dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
+dnl  see https://www.gnu.org/licenses/.
+
+
+defreg(r0,`%r``''0')
+defreg(r1,`%r``''1')
+defreg(r2,`%r``''2')
+defreg(r3,`%r``''3')
+defreg(r4,`%r``''4')
+defreg(r5,`%r``''5')
+defreg(r6,`%r``''6')
+defreg(r7,`%r``''7')
+defreg(r8,`%r``''8')
+defreg(r9,`%r``''9')
+defreg(r10,`%r``''10')
+defreg(r11,`%r``''11')
+defreg(r12,`%r``''12')
+defreg(r13,`%r``''13')
+defreg(r14,`%r``''14')
+defreg(r15,`%r``''15')
+defreg(ap,`%a``''p')
+
+define(`foo', blablabla)
+
+divert