bug#23261: 25.0.92; Undefined behavior in lib/stdint.h

[Philipp Stephani]

Clang finds the following undefined behavior in lib/stdint.h:

./lisp.h:3705:3: warning: shifting a negative signed value is undefined 
[-Wshift-negative-value]
  XSETPVECTYPE (XVECTOR (v), PVEC_SUB_CHAR_TABLE);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./lisp.h:1124:24: note: expanded from macro 'XSETPVECTYPE'
  ((v)->header.size |= PSEUDOVECTOR_FLAG | ((code) << PSEUDOVECTOR_AREA_BITS))
                       ^~~~~~~~~~~~~~~~~
./lisp.h:763:43: note: expanded from macro 'PSEUDOVECTOR_FLAG'
# define PSEUDOVECTOR_FLAG (PTRDIFF_MAX - PTRDIFF_MAX / 2)
                                          ^~~~~~~~~~~
../lib/stdint.h:520:5: note: expanded from macro 'PTRDIFF_MAX'
    _STDINT_MAX (1, 64, 0l)
    ^~~~~~~~~~~~~~~~~~~~~~~
../lib/stdint.h:126:8: note: expanded from macro '_STDINT_MAX'
   ? ~ _STDINT_MIN (signed, bits, zero) \
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../lib/stdint.h:122:31: note: expanded from macro '_STDINT_MIN'
  ((signed) ? (- ((zero) + 1) << ((bits) ? (bits) - 1 : 0)) : (zero))
               ~~~~~~~~~~~~~~ ^

Could we maybe just remove stdint.h completely?  It should always be
provided by the standard C library.



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