Force load the C++ standard library to make Mono happy

Author: filmor

clr_loader/ffi/__init__.py

@@ -35,6 +35,8 @@ def load_hostfxr(dotnet_root):
 
 
 def load_mono(path=None, gc=None):
+    # Preload C++ standard library, Mono needs that and doesn't properly link against it
+    ffi.dlopen("stdc++", ffi.RTLD_GLOBAL)
     if path is None:
         from ctypes.util import find_library