Just like almost every ./configure script out there, when configuring gnokii before compiling you can let the script automatically figure out what libraries you have got or you can explicitly enable or disable some features.
The features that will be available when version 0.6.15 is out are:

$ ./configure --help
  --disable-nls           do not use Native Language Support
  --enable-fulldebug      compile with full debugging support
  --enable-debug          compile with debug code
  --enable-xdebug         compile with xdebug code
  --enable-rlpdebug       compile with RLP debug code
  --enable-libical        enable libical support (default is autodetected)
  --enable-libusb         enable libusb support (default is autodetected)
  --enable-irda           enable irda support (default is autodetected)
  --enable-bluetooth      enable bluetooth support (default is autodetected)
  --enable-security       enable all security features

Note that you can't enable a feature if you haven't installed the needed libraries and/or includes (almost always you need a devel- package). Well, you can, but it will eventually fail.

The ./configure script accepts arguments in various formats; for example the following are all synonyms to enable the compiling of Bluetooth stuff:


or to disable it: