m4: avoid warnings about too-long initializer stringsHEADmain

Mark `digits` as `__non_string`, to avoid warnings from clang 21 similar
to:

    usr.bin/m4/misc.c:123:27: error: initializer-string for character array is too long, array size is 36 but initializer has size 37 (including the null terminating character); did you mean to use the 'nonstring' attribute? [-Werror,-Wunterminated-string-initialization]
      123 |         static char digits[36] = "0123456789abcdefghijklmnopqrstuvwxyz";
          |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

MFC after:	3 days

0 files changed, 0 insertions, 0 deletions