The OSM uses software called 'FCM' to handle the compilation of the code. FCM is distributed in the tarball downloaded from the ftp site.
Before trying to compile, make sure the FCM directory is added to your PATH environment variable so the fcm command can be found (if you already have fcm available on your system, we still recommend using the distributed version):
e.g. assuming osm is unpacked in $HOME/ecmwf/osm/
export PATH=$PATH:$HOME/ecmwf/osm/fcm/bin
Build configuration
At ECMWF...
The script compile_fcm.ksh is provided that correctly sets the compilation environment by using module load command and then compiling the model code using the command fcm. You may need to edit this script for your own account name and directories.