I created gcc projects for K20/K60 back in the March this year. I finally realized I could update my makefile and startups for CMSIS files and of course, for the freedom platform. Time's up!
The initial version contains the gpio demo for the FRDM-KL25Z. Here's the link Kinetis L ARM GCC demo using CMSIS files [github.com/0xc0170]
If you have any problems, questions, leave a comment as usual. I will add more freedom platform by time.