Hint: used config file '/etc/nim.cfg' [Conf] Hint: system [Processing] Hint: ircclient [Processing] Hint: sockets [Processing] Hint: os [Processing] Hint: strutils [Processing] Hint: parseutils [Processing] Hint: times [Processing] Hint: posix [Processing] Hint: unsigned [Processing] ircclient.nim(1, 7) Warning: sockets is deprecated [Deprecated] Hint: threadpool [Processing] Hint: cpuinfo [Processing] Hint: linux [Processing] Hint: cpuload [Processing] Hint: locks [Processing] lib/nim/core/locks.nim(22, 43) Warning: LockEffect is deprecated [Deprecated] lib/nim/core/locks.nim(25, 44) Warning: LockEffect is deprecated [Deprecated]
Error: execution of an external program failed
Please either put your error in a code block, or give a link to a gist/pastebin site. Simply posting it as-is makes it rather hard to read.
With regards to your actual problem, what C compiler are you using (and what version)? Are you using the development version of the Nim compiler, or the stable release? What architecture are you running on?
An initial search of '__ATOMIC_SEQ_CST' shows that it's a GCC builtin, and this link suggests that, if you are using GCC, that your using an out-of-date version. Further reading of the various versions of the GCC manual shows that '__ATOMIC_SEQ_CST' and the other symbols were introduced in GCC 4.7.4 .