[RFC PATCH 1/3] search: fix "grep -Fif /dev/null"

[Paolo Bonzini]

* bootstrap.conf: Include gnulib module minmax.
* src/searchutils.c (mbtolower): Handle *N == 0 case.
* src/system.h: Include minmax.h from gnulib.
---
 bootstrap.conf    |    1 +
 src/searchutils.c |   11 ++++++-----
 src/system.h      |    1 +
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/bootstrap.conf b/bootstrap.conf
index 1da6823..77870fe 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -54,6 +54,7 @@ mbrlen
 mbrtowc
 memchr
 mempcpy
+minmax
 obstack
 open
 progname
diff --git a/src/searchutils.c b/src/searchutils.c
index 1192485..6f4a5d9 100644
--- a/src/searchutils.c
+++ b/src/searchutils.c
@@ -68,15 +68,16 @@ mbtolower (const char *beg, size_t *n)
   const char *end;
   char *p;
 
-  assert (0 < *n);
-
-  if (*n > outalloc)
+  if (*n > outalloc || outalloc == 0)
     {
-      out = xrealloc (out, *n);
-      outalloc = *n;
+      outalloc = MAX(1, *n);
+      out = xrealloc (out, outalloc);
     }
+
   /* appease clang-2.6 */
   assert (out);
+  if (*n == 0)
+    return out;
 
   memset (&is, 0, sizeof (is));
   memset (&os, 0, sizeof (os));
diff --git a/src/system.h b/src/system.h
index ee85b22..a0d3c4a 100644
--- a/src/system.h
+++ b/src/system.h
@@ -23,6 +23,7 @@
 #include "binary-io.h"
 #include "configmake.h"
 #include "dirname.h"
+#include "minmax.h"
 
 #if O_BINARY
 # define HAVE_DOS_FILE_CONTENTS 1
-- 
1.7.1