[Toybox] grep doesn't allocate enough space

[William Haddon]

Grep miscalculates the amount of memory it needs to allocate when  
"converting strings to one big regex" when the -e flag is not  
specified. Since in this case "\|" is inserted between strings rather  
than "|", two extra bytes rather than one need to be provided for each  
string. I noticed this because it caused grep to seg-fault on musl when  
a regex of exactly seven characters is provided. I've included the  
patch to fix it below.

William Haddon

diff -rupN toybox-0.4.6/toys/posix/grep.c src/toys/posix/grep.c
--- toybox-0.4.6/toys/posix/grep.c	2013-09-11 17:09:53.000000000  
+0000
+++ src/toys/posix/grep.c	2013-10-21 20:52:24.000000000 +0000
@@ -212,7 +212,8 @@ static void parse_regex(void)

      // Convert strings to one big regex
      if (w) len = 36;
-    for (al = TT.e; al; al = al->next) len += strlen(al->arg)+1;
+    for (al = TT.e; al; al = al->next)
+      len += strlen(al->arg)+1+!(toys.optflags & FLAG_E);

      regstr = s = xmalloc(len);
      if (w) s = stpcpy(s, "(^|[^_[:alnum:]])(");
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