tccgen: reset aligned attribute for next type

Basically, with:
    typedef __attribute__((aligned(16))) struct _xyz {
         ...
    } xyz, *pxyz;

we want the struct aligned but not the pointer.

FIXME: This patch is a hack, waiting for someone in the knowledge
of correct __attribute__ semantics.

tccgen.c

@@ -5738,6 +5738,7 @@ static int decl0(int l, int is_for_loop_init)
                 }
                 next();
             }
+            ad.aligned = 0;
         }
     }
     return 0;