[PATCH] Fix warning -Wchar-subscripts in isspace() and isdigit() macro

[Aschref Ben-Thabet]

From: Aschref Ben Thabet <aschref.ben-thabet at embedded-brains.de>

The warning may be because you're passing a char to the isspace() macro.
The implementation of isspace() may be via array indexing.
(The argument to the isspace()/isdegit() macro is defined to be an
unsigned char the value of which can fit in an unsignedchar).

at ctype.h in GNU libc, and while there's a complicated mess of macros
and functions, somewhere in the definition of isspace() there's an array
being indexed.

See if isspace((unsigned char) *str) gets rid of the warning.

The s[r + b] is very likely a bug, because the type char can be signed
or unsigned—it's up to the compiler. If char is signed, then it's
possible for c to be negative, in which case accessing a negative array
index leads to Undefined Behavior.
---
 cpukit/libdl/rtl-archive.c                 | 4 ++--
 cpukit/libmisc/rtems-fdt/rtems-fdt-shell.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/cpukit/libdl/rtl-archive.c b/cpukit/libdl/rtl-archive.c
index eb7641b034..8f280157ff 100644
--- a/cpukit/libdl/rtl-archive.c
+++ b/cpukit/libdl/rtl-archive.c
@@ -516,13 +516,13 @@ rtems_rtl_archives_load_config (rtems_rtl_archives* archives)
       {
         size_t ls = strlen (&s[r]);
         size_t b = 0;
-        while (b < ls && isspace (s[r + b]))
+        while (b < ls && isspace((unsigned char)(s[r + b])))
         {
           s[r + b] = '\0';
           ++b;
         }
         b = ls - 1;
-        while (b > 0 && isspace (s[r + b]))
+        while (b > 0 && isspace((unsigned char)(s[r + b])))
         {
           s[r + b] = '\0';
           --b;
diff --git a/cpukit/libmisc/rtems-fdt/rtems-fdt-shell.c b/cpukit/libmisc/rtems-fdt/rtems-fdt-shell.c
index 32c9c6e17e..30002bc804 100644
--- a/cpukit/libmisc/rtems-fdt/rtems-fdt-shell.c
+++ b/cpukit/libmisc/rtems-fdt/rtems-fdt-shell.c
@@ -338,7 +338,7 @@ rtems_fdt_shell_set (int argc, char *argv[])
   if (!rtems_fdt_get_value32 (argv[1], "reg", sizeof (uint32_t), &address))
     return 1;
 
-  if (isdigit((int)argv[mask_arg][0]))
+  if (isdigit((unsigned char)argv[mask_arg][0]))
     mask = strtoul (argv[mask_arg], 0, 0);
   else
   {
-- 
2.26.2