explicitly set WARNS for modules that fail with WARNS=5.
Also, turn on -Wno-missing-noreturn for clang for some files.
At the moment, among ~ 360 modules,
- 2 (lua and zfs) need WARNS=0
- 1 (solaris) needs WARNS=1
- 136 need WARNS=3 (mostly due to sign-compare)
- 4 need WARNS=4
- others can be compiled with WARNS=5
Discussed on tech-kern.
The four modules are apple_smc for the core functions, apple_smc_acpi
for attachment at acpi, and apple_smc_fan & apple_smc_temp for stuff
on the SMC.
Seems like there's a lot more bookkeeping necessary to maintain
children of an applesmc device implemented by loadable modules.
Maybe there's a better way I just haven't figured out yet.
