config: Fix doveconf section output when char is unsigned

This happened at least with ARM CPU.

diff --git a/src/config/doveconf.c b/src/config/doveconf.c
index 81a6358b414f9a2717ccebd675c9c838ef1fecb5..bd990df7bb99c32983804de95a5fcffcbcaf3d80 100644 (file)
--- a/src/config/doveconf.c
+++ b/src/config/doveconf.c
@@ -104,7 +104,7 @@ static int config_string_cmp(const char *const *p1, const char *const *p2)
        if (s2[i] == '=')
                return 1;
 
-       return s1[i] - s2[i];
+       return (signed char)s1[i] - (signed char)s2[i];
 }
 
 static struct prefix_stack prefix_stack_pop(ARRAY_TYPE(prefix_stack) *stack)