Revert "Enable link time garbage collection when link time optimization is enabled"

Some linker on different platforms don't handle the garbage collection
correctly and create extreme bloated binaries. Therefore, leave it to the user
to enable this feature or not.
Use localtime for windows compatibility

localtime_r is prefered because it has no shared states. It creates less
problems when using threads or calling it multiple times with different
parameters. Mupen64plus doesn't do this right now, but has many workarounds for
windows compilers which don't work all the time and need extra workarounds
later. Using localtime instead may be the easiest solution right now.