Commit Briefs
add O_CLOEXEC (close-on-exec) flag to open(2) calls
suggested by millert ok thomas_adam
portable: initial Linux compilation
This commit modifies the GoT main branch to be able to compile it under linux.
got_error_from_errno -> got_error_prefix_errno
also add got_error_prefix_errno2 and got_error_prefix_errno3 which should hopefully all be merged into a single function with variadic args (but can't alloc mem)