This very simple WML compiler is based on the wml_tester.c example. 
In order to compile it, take the archive of Kannel Gateway, extract 
it and copy the wmlc.c file to the test/ directory. 

  $ tar zxf gateway-1.0.3.tar.gz
  $ cp /path/to/wmlc.c gateway-1.0.3/test
  $ cd gateway-1.0.3
  $ ./configure
  $ make tests

The binary will be located in test/wmlc. You can then copy it to 
/usr/local/bin for example.