Fix setjmp/longjmp on native Windows (#1331)

* Add setjmp wrapper

* Add to projects

* Use wrapper on x64

* Always build on x64 and exclude on win32

* Fix signature

* Add comments

* Add comments for os-win32.h

* Add extern decleration

* Support cmake Windows build

* Fix for MinGW

qemu/include/sysemu/os-win32.h

@@ -56,13 +56,27 @@
 # define EWOULDBLOCK  WSAEWOULDBLOCK
 #endif
 
-#if defined(_WIN64) && !defined(_MSC_VER)
+#if defined(_WIN64)
 /* On w64, setjmp is implemented by _setjmp which needs a second parameter.
  * If this parameter is NULL, longjump does no stack unwinding.
  * That is what we need for QEMU. Passing the value of register rsp (default)
  * lets longjmp try a stack unwinding which will crash with generated code. */
+
+#if defined(_MSC_VER) // MSVC
+
+// See qemu/include/utils/setjmp-wrapper-win32.asm for details.
+extern int _setjmp_wrapper(jmp_buf);
+
+# undef setjmp
+# define setjmp(env) _setjmp_wrapper(env)
+
+#else // MinGW
+
+// Original QEMU patch.
 # undef setjmp
 # define setjmp(env) _setjmp(env, NULL)
+#endif
+
 #endif
 /* QEMU uses sigsetjmp()/siglongjmp() as the portable way to specify
  * "longjmp and don't touch the signal masks". Since we know that the