[Bug-tar] minor warning glitch in tar 1.19 on Solaris 8 (sparc) with GCC 4.2.1

[Paul Eggert]

Building GNU tar with GCC 4.2.1 on a machine where char is unsigned
elicits this bogus warning:

utf8.c: In function 'string_ascii_p':
utf8.c:94: warning: comparison is always true due to limited range of data type
mv -f .deps/utf8.Tpo .deps/utf8.Po

I observed the problem on Solaris 8 (sparc) but I imagine it happens
elsewhere.  I installed this patch:

2007-10-12  Paul Eggert  <address@hidden>

        * src/utf8.c (string_ascii_p): Recode to avoid bogus GCC 4.2.1
        warning about "comparison is always true due to limited range of
        data type" when char is unsigned.

--- src/utf8.c  27 Jun 2007 13:30:15 -0000      1.10
+++ src/utf8.c  13 Oct 2007 05:49:15 -0000
@@ -91,7 +91,7 @@ bool
 string_ascii_p (char const *p)
 {
   for (; *p; p++)
-    if (! (0 <= *p && *p <= 127))
+    if (*p & ~0x7f)
       return false;
   return true;
 }