Sync with gnulib 6ed53f13bc39d9a0252549e98a2a59441fb2351f.

lib/strutil/xstrtol.c: prohibit monstrosities like "1bB".

Problem reported by Young Mo Kang in: http://bugs.gnu.org/23388.

(xstrtoumax): Allow trailing second suffixes like "B" only if the first
suffix needs a base.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

lib/strutil/xstrtol.c

@@ -142,6 +142,20 @@ xstrtoumax (const char *s, char **ptr, int base, uintmax_t * val, const char *va
 
         base = 1024;
 
+        switch (**p)
+        {
+        case 'E':
+        case 'G':
+        case 'g':
+        case 'k':
+        case 'K':
+        case 'M':
+        case 'm':
+        case 'P':
+        case 'T':
+        case 't':
+        case 'Y':
+        case 'Z':
             if (strchr (valid_suffixes, '0') != NULL)
             {
                 /* The "valid suffix" '0' is a special flag meaning that
@@ -167,6 +181,9 @@ xstrtoumax (const char *s, char **ptr, int base, uintmax_t * val, const char *va
                     break;
                 }
             }
+        default:
+            break;
+        }
 
         switch (**p)
         {
@@ -175,6 +192,9 @@ xstrtoumax (const char *s, char **ptr, int base, uintmax_t * val, const char *va
             break;
 
         case 'B':
+            /* This obsolescent first suffix is distinct from the 'B'
+               second suffix above.  E.g., 'tar -L 1000B' means change
+               the tape after writing 1000 KiB of data.  */
             overflow = bkm_scale (&tmp, 1024);
             break;