build error on msys2

[theotheroracle]

gcc -std=c99 -Wall -pedantic -Wextra -Werror -march=nocona -msahf -mtune=generic -O2 -pipe   -c -o jshon.o jshon.c
In file included from jshon.c:2:
jshon.c: In function ‘remove_jsonp_callback’:
jshon.c:425:44: error: array subscript has type ‘char’ [-Werror=char-subscripts]
  425 |     while (first < last && JSON_IDENTIFIER(*first))
      |                                            ^~~~~~
jshon.c:425:28: note: in expansion of macro ‘JSON_IDENTIFIER’
  425 |     while (first < last && JSON_IDENTIFIER(*first))
      |                            ^~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make: *** [<builtin>: jshon.o] Error 1
==> ERROR: A failure occurred in build().

build if i remove the -Werror flag, i'm not sure why that's part of the makefile tbh