With -buildmode=c-archive, initsig is called before the memory
allocator has been initialized. The code was doing a memory
allocation because of the call to funcPC(sigtramp). When escape
analysis is fully implemented, that call should not allocate. For
now, finesse the issue by calling a C function to get the C function
pointer value of sigtramp.
When returning from a call from C to a Go function, a deferred
function is run to go back to syscall mode. When the call occurs on a
non-Go thread, that call sets g to nil, making it impossible to add
the _defer struct back to the pool. Just drop it and let the garbage
collector clean it up.
Reviewed-on: https://go-review.googlesource.com/33675
From-SVN: r242992
fbe9724cc3