Minor regex config changes, fixed KMP search code.

[SVN r10115]

include/boost/regex/detail/regex_config.hpp

@@ -307,10 +307,10 @@ full list of macros and their usage.
 #   endif
 #endif
 
-#ifdef _REENTRANT
+#if defined(_REENTRANT) || defined(_PTHREADS)
 //
-// several compilers define _REENTRANT when 
-// threading support is turned on:
+// Several compilers define _REENTRANT or 
+// _PTHREADS when threading support is turned on:
 //
 #define BOOST_RE_THREADS
 #endif

include/boost/regex/detail/regex_match.hpp

@@ -1192,13 +1192,13 @@ unsigned int reg_grep2(Predicate foo, I first, I last, const reg_expression<char
                ++cmatches;
                if(foo(m) == false)
                   return cmatches;
+               if(m[0].second == last)
+                  return cmatches;
                _skip_and_inc(clines, last_line, first, restart);
                next_base = m[0].second;
                pd.temp_match.init_fail(next_base, last);
                m.init_fail(next_base, last);
                j = 0;
-               if(m[0].second == last)
-                  return cmatches;
             }
             else
             {