freebsd1# cd /usr/ports/www/firefox35
freebsd1# make showconfig
===> The following configuration options are available for firefox-3.5,1:
     DBUS=off "Enable D-BUS support"
     NEWTAB=on "Open external links in a new tab"
     SMB=off "Enable smb:// URI support using gnomevfs"
     DEBUG=off "Build a debugging image"
     LOGGING=off "Enable additional log messages"
     OPTIMIZED_CFLAGS=on "Enable some additional optimizations"
===> Use 'make config' to modify these settings