cc1: error: unrecognized command line option "-fvisibility=hidden"

$ gcc --version
gcc (GCC) 3.4.6 [FreeBSD] 20060305
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# cd /usr/ports/lang/gcc49
# make install clean