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/mpq/inv.c b/third_party/gmp/mpq/inv.c
new file mode 100644
index 0000000..c395984
--- /dev/null
+++ b/third_party/gmp/mpq/inv.c
@@ -0,0 +1,70 @@
+/* mpq_inv(dest,src) -- invert a rational number, i.e. set DEST to SRC
+ with the numerator and denominator swapped.
+
+Copyright 1991, 1994, 1995, 2000, 2001, 2012 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
+mpq_inv (mpq_ptr dest, mpq_srcptr src)
+{
+ mp_size_t num_size = SIZ(NUM(src));
+ mp_size_t den_size = SIZ(DEN(src));
+
+ if (num_size < 0)
+ {
+ num_size = -num_size;
+ den_size = -den_size;
+ }
+ else if (UNLIKELY (num_size == 0))
+ DIVIDE_BY_ZERO;
+
+ SIZ(DEN(dest)) = num_size;
+ SIZ(NUM(dest)) = den_size;
+
+ /* If dest == src we may just swap the numerator and denominator;
+ we ensured that the new denominator is positive. */
+
+ if (dest == src)
+ {
+ MP_PTR_SWAP (PTR(NUM(dest)), PTR(DEN(dest)));
+ MP_SIZE_T_SWAP (ALLOC(NUM(dest)), ALLOC(DEN(dest)));
+ }
+ else
+ {
+ mp_ptr dp;
+
+ den_size = ABS (den_size);
+ dp = MPZ_NEWALLOC (NUM(dest), den_size);
+ MPN_COPY (dp, PTR(DEN(src)), den_size);
+
+ dp = MPZ_NEWALLOC (DEN(dest), num_size);
+ MPN_COPY (dp, PTR(NUM(src)), num_size);
+ }
+}