turned errno() methods back into functions since they should already be thread safe

vm/io.cpp

@@ -258,24 +258,13 @@ PRIMITIVE(fclose)
 /* This function is used by FFI I/O. Accessing the errno global directly is
 not portable, since on some libc's errno is not a global but a funky macro that
 reads thread-local storage. */
-int factorvm::err_no()
+VM_C_API int err_no()
 {
 	return errno;
 }
 
-VM_C_API int err_no()
-{
-	return vm->err_no();
-}
-
-void factorvm::clear_err_no()
+VM_C_API void clear_err_no()
 {
 	errno = 0;
 }
-
-VM_C_API void clear_err_no()
-{
-	return vm->clear_err_no();
-}
-
 }

vm/vm.hpp

@@ -448,8 +448,6 @@ struct factorvm {
 	inline void vmprim_fseek();
 	inline void vmprim_fflush();
 	inline void vmprim_fclose();
-	int err_no();
-	void clear_err_no();
 
 	//code_gc
 	void clear_free_list(heap *heap);