Bring back strdup on optline in pg_ctl read_post_opts

The strdups were removed in a recent 8.4 postgres merge commit
fa287d01. Without them, pg_ctl restart will usually fail as the memory
is freed for optline. Bring them back similar to how it was fixed in
an earlier commit.

Reference commit by Daniel Gustafsson:
https://github.com/greenplum-db/gpdb/commit/627ba5d8d83caa133ed1d8c9e13570bd162933bf

src/bin/pg_ctl/pg_ctl.c

@@ -697,10 +697,10 @@ read_post_opts(void)
 				if ((arg1 = strstr(optline, " \"")) != NULL)
 				{
 					*arg1 = '\0';	/* terminate so we get only program name */
-					post_opts = arg1 + 1; /* point past whitespace */
+					post_opts = strdup(arg1 + 1); /* point past whitespace */
 				}
 				if (postgres_path == NULL)
-					postgres_path = optline;
+					postgres_path = strdup(optline);
 			}
 
 			/* Free the results of readfile. */