Add Chromium-only Blender WebEngine parity work

blender-5.2.0/extern/gmp-source/mpz/mul_2exp.c

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+/* mpz_mul_2exp -- Multiply a bignum by 2**CNT
+
+Copyright 1991, 1993, 1994, 1996, 2001, 2002, 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
+mpz_mul_2exp (mpz_ptr r, mpz_srcptr u, mp_bitcnt_t cnt)
+{
+  mp_size_t un, rn;
+  mp_size_t limb_cnt;
+  mp_ptr rp;
+  mp_srcptr up;
+  mp_limb_t rlimb;
+
+  un = ABSIZ (u);
+  limb_cnt = cnt / GMP_NUMB_BITS;
+  rn = un + limb_cnt;
+
+  if (un == 0)
+    rn = 0;
+  else
+    {
+      rp = MPZ_REALLOC (r, rn + 1);
+      up = PTR(u);
+
+      cnt %= GMP_NUMB_BITS;
+      if (cnt != 0)
+	{
+	  rlimb = mpn_lshift (rp + limb_cnt, up, un, cnt);
+	  rp[rn] = rlimb;
+	  rn += (rlimb != 0);
+	}
+      else
+	{
+	  MPN_COPY_DECR (rp + limb_cnt, up, un);
+	}
+
+      /* Zero all whole limbs at low end.  Do it here and not before calling
+	 mpn_lshift, not to lose for U == R.  */
+      MPN_ZERO (rp, limb_cnt);
+    }
+
+  SIZ(r) = SIZ(u) >= 0 ? rn : -rn;
+}