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

@@ -142,30 +142,47 @@ xstrtoumax (const char *s, char **ptr, int base, uintmax_t * val, const char *va
 
         base = 1024;
 
-        if (strchr (valid_suffixes, '0') != NULL)
+        switch (**p)
         {
-            /* The "valid suffix" '0' is a special flag meaning that
+        case 'E':
-               an optional second suffix is allowed, which can change
+        case 'G':
-               the base.  A suffix "B" (e.g. "100MB") stands for a power
+        case 'g':
-               of 1000, whereas a suffix "iB" (e.g. "100MiB") stands for
+        case 'k':
-               a power of 1024.  If no suffix (e.g. "100M"), assume
+        case 'K':
-               power-of-1024.  */
+        case 'M':
-
+        case 'm':
-            switch (p[0][1])
+        case 'P':
+        case 'T':
+        case 't':
+        case 'Y':
+        case 'Z':
+            if (strchr (valid_suffixes, '0') != NULL)
             {
-            case 'i':
+                /* The "valid suffix" '0' is a special flag meaning that
-                if (p[0][2] == 'B')
+                   an optional second suffix is allowed, which can change
-                    suffixes += 2;
+                   the base.  A suffix "B" (e.g. "100MB") stands for a power
-                break;
+                   of 1000, whereas a suffix "iB" (e.g. "100MiB") stands for
+                   a power of 1024.  If no suffix (e.g. "100M"), assume
+                   power-of-1024.  */
 
-            case 'B':
+                switch (p[0][1])
-            case 'D':          /* 'D' is obsolescent */
+                {
-                base = 1000;
+                case 'i':
-                suffixes++;
+                    if (p[0][2] == 'B')
-                break;
+                        suffixes += 2;
-            default:
+                    break;
-                break;
+
+                case 'B':
+                case 'D':      /* 'D' is obsolescent */
+                    base = 1000;
+                    suffixes++;
+                    break;
+                default:
+                    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;