don't be fooled into emitting padding for wpos when not used

src/mesa/drivers/dri/i915/i915_fragprog.c

@@ -788,7 +788,7 @@ static void check_wpos( struct i915_fragment_program *p )
    GLuint inputs = p->FragProg.InputsRead;
    GLint i;
 
-   p->wpos_tex = 0;
+   p->wpos_tex = -1;
 
    for (i = 0; i < p->ctx->Const.MaxTextureCoordUnits; i++) {
       if (inputs & FRAG_BIT_TEX(i)) 

src/mesa/drivers/dri/i915/i915_program.c

@@ -380,7 +380,7 @@ void i915_init_program( i915ContextPtr i915, struct i915_fragment_program *p )
    p->decl_t = 0;
    p->temp_flag = 0xffff000;
    p->utemp_flag = ~0x7;
-   p->wpos_tex = 0;
+   p->wpos_tex = -1;
    p->depth_written = 0;
    p->nr_params = 0;