How does one rebuild libsam_sam3x8e?


I'm trying to make some enhancements to the libsam counter/timer library. Building my project doesn't seem to rebuild the tc code, which I believe may be compiled into the libsam_sam3x8e_gcc.rel.a file in C:\Arduino\Arduino 1.5.7\hardware\arduino\sam\variants\arduino_due_x. I'm not familiar with the Atmel tools. Can someone tell me how to rebuild this code? I suspect it's a matter of invoking the compiler using the make file in C:\Arduino\Arduino 1.5.7\hardware\arduino\sam\variants\arduino_due_x\build_gcc .