locale.c: Silence '-Wchar-subscripts' C++ warning

In, for example,
nntp.perl.org/group/perl.daily-build.reports/2022/10/msg285932.html

we get:

locale.c:2281:27: warning: array subscript is of type 'char'
[-Wchar-subscripts]
locale.c:2282:27: warning: array subscript is of type 'char'
[-Wchar-subscripts]

These warnings are bogus, but better to avoid them.

1 files changed, 7 insertions, 2 deletions

diff --git a/locale.c b/locale.c
index 9d86487a9a..ef2c8cefc0 100644
--- a/locale.c
+++ b/locale.c
@@ -2340,8 +2340,13 @@ S_new_ctype(pTHX_ const char *newctype)
         if (bad_count == 2 && maybe_utf8_turkic) {
             bad_count = 0;
             *bad_chars_list = '\0';
-            PL_fold_locale['I'] = 'I';
-            PL_fold_locale['i'] = 'i';
+
+            /* The casts are because otherwise some compilers warn:
+                gcc.gnu.org/bugzilla/show_bug.cgi?id=99950
+                gcc.gnu.org/bugzilla/show_bug.cgi?id=94182
+             */
+            PL_fold_locale[ (U8) 'I' ] = 'I';
+            PL_fold_locale[ (U8) 'i' ] = 'i';
             PL_in_utf8_turkic_locale = TRUE;
             DEBUG_L(PerlIO_printf(Perl_debug_log, "%s is turkic\n", newctype));
         }