Use ATTRIBUTE_MAY_ALIAS where alias violations are likely

In particular, alias violations are likely for the return values of
dlsym(3), which get cast around arbitrarily.

* src/emacs-module.c (Fmodule_load): Use ATTRIBUTE_MAY_ALIAS.

src/dynlib.h

@@ -24,11 +24,14 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 typedef void *dynlib_handle_ptr;
 dynlib_handle_ptr dynlib_open (const char *path);
-void *dynlib_sym (dynlib_handle_ptr h, const char *sym);
-typedef struct dynlib_function_ptr_nonce *(*dynlib_function_ptr) (void);
-dynlib_function_ptr dynlib_func (dynlib_handle_ptr h, const char *sym);
-const char *dynlib_error (void);
 int dynlib_close (dynlib_handle_ptr h);
+const char *dynlib_error (void);
+
+ATTRIBUTE_MAY_ALIAS void *dynlib_sym (dynlib_handle_ptr h, const char *sym);
+
+typedef struct dynlib_function_ptr_nonce *(ATTRIBUTE_MAY_ALIAS *dynlib_function_ptr) (void);
+dynlib_function_ptr dynlib_func (dynlib_handle_ptr h, const char *sym);
+
 /* Sets *FILE to the file name from which PTR was loaded, and *SYM to
    its symbol name.  If the file or symbol name could not be
    determined, set the corresponding argument to NULL.  */

src/emacs-module.c

@@ -658,7 +658,7 @@ funcall_module (Lisp_Object function, ptrdiff_t nargs, Lisp_Object *arglist)
   initialize_environment (&pub, &priv);
 
   USE_SAFE_ALLOCA;
-  emacs_value *args;
+  ATTRIBUTE_MAY_ALIAS emacs_value *args;
   if (plain_values)
     args = (emacs_value *) arglist;
   else