diff -ruN a/config/nim.cfg b/config/nim.cfg
--- a/config/nim.cfg	2018-01-06 22:48:43.920598426 +0100
+++ b/config/nim.cfg	2018-01-06 22:49:43.620979479 +0100
@@ -9,6 +9,7 @@
 #  gcc.path %= "$CC_PATH"
 
 cc = gcc
+define:nimCoroutinesSetjmp
 
 # additional options always passed to the compiler:
 --parallel_build: "0" # 0 to auto-detect number of processors