Release Cosmopolitan v3.8.0

This change switches c++ exception handling from sjlj to standard dwarf.
It's needed because clang for aarch64 doesn't support sjlj. It turns out
that libunwind had a bare-metal configuration that made this easy to do.

This change gets the new experimental cosmocc -mclang flag in a state of
working so well that it can now be used to build all of llamafile and it
goes 3x faster in terms of build latency, without trading away any perf.

The int_fast16_t and int_fast32_t types are now always defined as 32-bit
in the interest of having more abi consistency between cosmocc -mgcc and
-mclang mode.

third_party/intel/clang/usermsrintrin.h

@@ -0,0 +1,51 @@
+/*===--------------- usermsrintrin.h - USERMSR intrinsics -----------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+#ifndef __X86GPRINTRIN_H
+#error "Never use <usermsrintrin.h> directly; include <x86gprintrin.h> instead."
+#endif // __X86GPRINTRIN_H
+
+#ifndef __USERMSRINTRIN_H
+#define __USERMSRINTRIN_H
+#ifdef __x86_64__
+
+/// Reads the contents of a 64-bit MSR specified in \a __A into \a dst.
+///
+/// This intrinsic corresponds to the <c> URDMSR </c> instruction.
+/// \param __A
+///    An unsigned long long.
+///
+/// \code{.operation}
+///    DEST := MSR[__A]
+/// \endcode
+static __inline__ unsigned long long
+    __attribute__((__always_inline__, __nodebug__, __target__("usermsr")))
+    _urdmsr(unsigned long long __A) {
+  return __builtin_ia32_urdmsr(__A);
+}
+
+/// Writes the contents of \a __B into the 64-bit MSR specified in \a __A.
+///
+/// This intrinsic corresponds to the <c> UWRMSR </c> instruction.
+///
+/// \param __A
+///    An unsigned long long.
+/// \param __B
+///    An unsigned long long.
+///
+/// \code{.operation}
+///    MSR[__A] := __B
+/// \endcode
+static __inline__ void
+    __attribute__((__always_inline__, __nodebug__, __target__("usermsr")))
+    _uwrmsr(unsigned long long __A, unsigned long long __B) {
+  return __builtin_ia32_uwrmsr(__A, __B);
+}
+
+#endif // __x86_64__
+#endif // __USERMSRINTRIN_H