Compilation warnings on 3.15 #1048

      src/msgspec/_core.c:3691:24: warning: shifting a negative signed value is undefined [-Wshift-negative-value]
       3691 |         if (x == (-1LL << 63)) {
            |                   ~~~~ ^
      src/msgspec/_core.c:10206:16: warning: '_PyLong_Sign' is deprecated [-Wdeprecated-declarations]
       10206 |     bool neg = _PyLong_Sign(obj) < 0;
             |                ^
      /Users/sobolev/.pyenv/versions/3.15-dev/include/python3.15/cpython/longobject.h:38:1: note: '_PyLong_Sign' has been explicitly marked deprecated here
         38 | Py_DEPRECATED(3.14) PyAPI_FUNC(int) _PyLong_Sign(PyObject *v);
            | ^
      /Users/sobolev/.pyenv/versions/3.15-dev/include/python3.15/pyport.h:261:54: note: expanded from macro 'Py_DEPRECATED'
        261 | #define Py_DEPRECATED(VERSION_UNUSED) __attribute__((__deprecated__))
            |                                                      ^
      src/msgspec/_core.c:12037:19: warning: shifting a negative signed value is undefined [-Wshift-negative-value]
       12037 |     if (x < (-1LL << 53)) return false;
             |              ~~~~ ^
      3 warnings and 1 error generated.
      error: command '/usr/bin/clang' failed with exit code 1

» clang --version
Apple clang version 17.0.0 (clang-1700.6.3.2)
Target: arm64-apple-darwin24.6.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin