meson.build: compile with -fno-strict-aliasing

I tested that older compilers don't refuse this option:
 - gcc 4.8 (as that's the default in CentOS 7)
 - llvm 3.8 (year 2016 is enough, I hope)
12 jobs for strict-aliasing
in 185 minutes and 53 seconds and was queued for 1 second
Scheduled