[CMake] Linux release build w/out asserts

[Jon Trauntvein]

I have a Linux project that I am building using cmake.  Based upon my
experience with visual studio, I would expect the following differences
between the release and debug builds:

  - debug symbols not included by default
  - Optimisation differences
  - Disabling of debug tools like assert()

I have found that the assert() function is still being compiled into my
executable because the process aborts when an asserted condition is
encountered.  That said and recognising that this may well be
off-topic,  how do I go about disabling asserts using cmake?

Regards,

Jon Trauntvein