Allow blead to compile under some g++

Various platforms are refusing to compile blead with g++ [perl #121151]
This patch, suggested by Tony Cook seems to work.  There may be a better
way to do it, so I'm not closing the ticket, but this gets things
working again.

ext/SDBM_File/Makefile.PL

@@ -20,7 +20,6 @@ WriteMakefile(
               XSPROTOARG => '-noprototypes', 		# XXX remove later?
               VERSION_FROM => 'SDBM_File.pm',
               DEFINE => $define,
-	      PERL_MALLOC_OK => 1,
              );
 
 # We don't want the default subdir rule, as it creates a race condition with the