[interp] Fix compiler issue

We use the address of this label during EH to resume to it. For whatever reason, with some compilers, if the label is followed by a void return, the address of the label is at the end of the method, so we can't resume to it because it points to foreign code. We return NULL to workaround this.

mono/mini/interp/interp.c

@@ -1497,7 +1497,7 @@ interp_to_native_trampoline (gpointer addr, gpointer ccontext)
 #ifdef _MSC_VER
 #pragma optimize ("", off)
 #endif
-static MONO_NO_OPTIMIZATION MONO_NEVER_INLINE void
+static MONO_NO_OPTIMIZATION MONO_NEVER_INLINE gpointer
 ves_pinvoke_method (
 	InterpMethod *imethod,
 	MonoMethodSignature *sig,
@@ -1595,7 +1595,7 @@ ves_pinvoke_method (
 #endif
 	goto exit_pinvoke; // prevent unused label warning in some configurations
 exit_pinvoke:
-	return;
+	return NULL;
 }
 #ifdef _MSC_VER
 #pragma optimize ("", on)
@@ -2122,7 +2122,7 @@ do_icall (MonoMethodSignature *sig, int op, stackval *sp, gpointer ptr, gboolean
 #pragma optimize ("", off)
 #endif
 // Do not inline in case order of frame addresses matters, and maybe other reasons.
-static MONO_NO_OPTIMIZATION MONO_NEVER_INLINE void
+static MONO_NO_OPTIMIZATION MONO_NEVER_INLINE gpointer
 do_icall_wrapper (InterpFrame *frame, MonoMethodSignature *sig, int op, stackval *sp, gpointer ptr, gboolean save_last_error)
 {
 	MonoLMFExt ext;
@@ -2134,7 +2134,7 @@ do_icall_wrapper (InterpFrame *frame, MonoMethodSignature *sig, int op, stackval
 
 	goto exit_icall; // prevent unused label warning in some configurations
 exit_icall:
-	return;
+	return NULL;
 }
 #ifdef _MSC_VER
 #pragma optimize ("", on)