move -d:nimRawSetjmp to nim.cfg (#114)

Refs status-im/nimbus-build-system#44

Author: narimiran

.github/workflows/ci.yml

@@ -160,10 +160,6 @@ jobs:
 
       - name: Run tests
         run: |
-          if [[ "${{ matrix.target.os }}" == "windows" ]]; then
-            # https://github.com/status-im/nimbus-eth2/issues/3121
-            export NIMFLAGS="-d:nimRawSetjmp"
-          fi
           nim --version
           nimble --version
           nimble install -y --depsOnly

nim.cfg

@@ -0,0 +1,5 @@
+# Avoid some rare stack corruption while using exceptions with a SEH-enabled
+# toolchain: https://github.com/status-im/nimbus-eth2/issues/3121
+@if windows and not vcc:
+  --define:nimRawSetjmp
+@end