Patch for broken <cerrno>.

[SVN r31131]

include/boost/config/compiler/borland.hpp

@@ -56,6 +56,11 @@
       // fix broken <cstring> so that Boost.test works:
 #     include <cstring>
 #     undef strcmp
+#  endif
+   // fix broken errno declaration:
+#  include <errno.h>
+#  ifndef errno
+#     define errno errno
 #  endif
 
 //