Remove compiler warnings on Solaris 8.
Can go into 2.2.x, but not necessary.
diff --git a/Modules/_hotshot.c b/Modules/_hotshot.c
index 97037ac..2eb7bdb 100644
--- a/Modules/_hotshot.c
+++ b/Modules/_hotshot.c
@@ -1453,7 +1453,7 @@
     char *buffer;
     int i = 0;
 
-    while (*rev && !isdigit(*rev))
+    while (*rev && !isdigit((int)*rev))
         ++rev;
     while (rev[i] != ' ' && rev[i] != '\0')
         ++i;