RexxCC version 3.23 (2014/09/13) is available as open source software under the CDDL v1 license.
http://bnsmb.de/os2/rexxcc.html
"REXXCC can be used to "compile" or compress an REXX program. REXXCC "compiles" an OS/2 REXX program by substituting the source code with mostly any text. This is possible because the OS/2 REXX interpreter stores a tokenized copy of each executed REXX program in the EAs of the program. If you execute an OS/2 REXX program, the OS/2 REXX interpreter first checks if the tokenized copy in the EAs is still valid and, if so, executes the tokenized copy and ignores the source code."
URL: http://bnsmb.de/index.html
Special thanks to Bernd Schemmer for releasing it as open source.