ctx,st3m: increment the frame-clock of the texture cache context

All the contexts share the texture and eid handling of the "master" ctx context, which is within the rasterizer of the rendering context for framebuffer 0. For the age-tracking to work right we need to have a logical clock tied to the use of textures, this adds a small convenience function to the ctx implementation to inject an appropriate increment of this clock per rendered frame. This makes the ejection policy of discarding a least frequently used eid, which works well with eids created on demand and cached by an identity.

components/ctx/ctx.h

-/* ctx git commit: 4349079e */
+/* ctx git commit: aeaa8b2b */
 /* 
  * ctx.h is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -2509,6 +2509,10 @@ void ctx_vt_write (Ctx *ctx, uint8_t byte);
 int ctx_vt_has_data (Ctx *ctx);
 int ctx_vt_read (Ctx *ctx);
+
+void ctx_set_textureclock (Ctx *ctx, int frame);
+int  ctx_textureclock (Ctx *ctx);
+
 #ifdef __cplusplus
 }
 #endif
@@ -6121,8 +6125,7 @@ void ctx_buffer_set_data (CtxBuffer *buffer,
                           void (*freefunc) (void *pixels, void *user_data),
                           void *user_data);
-int _ctx_set_frame (Ctx *ctx, int frame);
-int _ctx_frame (Ctx *ctx);
+int ctx_textureclock (Ctx *ctx);
 void ctx_exit (Ctx *ctx);
@@ -53372,14 +53375,15 @@ void ctx_texture (Ctx *ctx, const char *eid, float x, float y)
     //fclose (f);
 }
 int
-_ctx_frame (Ctx *ctx)
+ctx_textureclock (Ctx *ctx)
 {
    return ctx->frame;
 }
-int
-_ctx_set_frame (Ctx *ctx, int frame)
+
+void
+ctx_set_textureclock (Ctx *ctx, int textureclock)
 {
-   return ctx->frame = frame;
+   ctx->frame = textureclock;
 }
 void ctx_define_texture (Ctx *ctx,
@@ -60980,8 +60984,8 @@ static void vt_ctx_exit (void *data)
   vt->current_line->ctx = vt->current_line->ctx_copy;
   vt->current_line->ctx_copy = tmp;
-  _ctx_set_frame (vt->current_line->ctx, _ctx_frame (vt->current_line->ctx) + 1);
-  _ctx_set_frame (vt->current_line->ctx_copy, _ctx_frame (vt->current_line->ctx));
+  ctx_set_textureclock (vt->current_line->ctx, ctx_textureclock (vt->current_line->ctx) + 1);
+  ctx_set_textureclock (vt->current_line->ctx_copy, ctx_textureclock (vt->current_line->ctx));
 #if 1
   if (vt->ctxp) // XXX: ugly hack to aid double buffering
     ((void**)vt->ctxp)[0]= vt->current_line->ctx;
@@ -67126,7 +67130,7 @@ void vt_draw (VT *vt, Ctx *ctx, double x0, double y0)
             if (line->ctx_copy)
               {
-                //fprintf (stderr, " [%i]\n", _ctx_frame (ctx));
+                //fprintf (stderr, " [%i]\n", ctx_textureclock (ctx));
                 //ctx_render_stream (line->ctx_copy, stderr, 1);
                 ctx_begin_path (ctx);