[PATCH v2] Fix error: array subscript has type 'char'

[Manuel Bouyer <bouyer@xxxxxxxxxx>]

Use unsigned char variable, or cast to (unsigned char), for
tolower()/islower() and friends. Fix compiler error
array subscript has type 'char' [-Werror=char-subscripts]

Signed-off-by: Manuel Bouyer <bouyer@xxxxxxxxxx>
Reviewed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Release-Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
 tools/libs/light/libxl_qmp.c | 2 +-
 tools/xentrace/xentrace.c    | 2 +-
 xen/tools/symbols.c          | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/libs/light/libxl_qmp.c b/tools/libs/light/libxl_qmp.c
index c394000ea9..9b638e6f54 100644
--- a/tools/libs/light/libxl_qmp.c
+++ b/tools/libs/light/libxl_qmp.c
@@ -1249,7 +1249,7 @@ static int qmp_error_class_to_libxl_error_code(libxl__gc 
*gc,
                 se++;
                 continue;
             }
-            if (tolower(*s) != tolower(*se))
+            if (tolower((unsigned char)*s) != tolower((unsigned char)*se))
                 break;
             s++, se++;
         }
diff --git a/tools/xentrace/xentrace.c b/tools/xentrace/xentrace.c
index 4b50b8a53e..a8903ebf46 100644
--- a/tools/xentrace/xentrace.c
+++ b/tools/xentrace/xentrace.c
@@ -957,7 +957,7 @@ static int parse_cpumask_range(const char *mask_str, 
xc_cpumap_t map)
 {
     unsigned int a, b;
     int nmaskbits;
-    char c;
+    unsigned char c;
     int in_range;
     const char *s;
 
diff --git a/xen/tools/symbols.c b/xen/tools/symbols.c
index 9f9e2c9900..0b12452616 100644
--- a/xen/tools/symbols.c
+++ b/xen/tools/symbols.c
@@ -173,11 +173,11 @@ static int read_symbol(FILE *in, struct sym_entry *s)
        /* include the type field in the symbol name, so that it gets
         * compressed together */
        s->len = strlen(str) + 1;
-       if (islower(stype) && filename)
+       if (islower((unsigned char)stype) && filename)
                s->len += strlen(filename) + 1;
        s->sym = malloc(s->len + 1);
        sym = SYMBOL_NAME(s);
-       if (islower(stype) && filename) {
+       if (islower((unsigned char)stype) && filename) {
                sym = stpcpy(sym, filename);
                *sym++ = '#';
        }
-- 
2.29.2