The acceptance case stops asking for a header it no longer needs

The imported-bindings program was skipped without FLAN_RAYLIB_H, which was
right when the bindings only existed if a header was read and is now the one
gate hiding the change. It runs on the same terms as every other raylib case:
libraylib linkable, no raylib-devel. A generated.flan regenerated empty or
stale is now caught on an ordinary machine rather than only on one with a
header exported.

Reach.link already answers the shim worry BUILT.md's cold-build attribution
would otherwise raise: sand.flan links 110 wrappers, not 425, because the
bindings nothing reachable calls are dropped. What is left is 65ms of frontend
on a cold build, against a header read that was 60-90ms of a fresh session and
15.5ms of every redefinition. Both numbers are in BUILT.md now.

Also a swallowed line continuation in the exclusion message.

BUILT.md

@@ -437,6 +437,37 @@ split this change exists to remove. The C symbol is kept verbatim in
 `Ast.DeclareC` either way, so a rename costs nothing: it is still what is
 called and still what the check compares against.
 
+#### What committing 253 more declarations costs, measured
+
+The section above says the cost is the check. That is the cost that mattered,
+but it is not the only one, and this file does not omit measured numbers.
+
+Every build now carries 425 `declare-c` where a default build carried 172, and
+the obvious worry is the shim: BUILT.md's own cold-build attribution above
+blames "the object cache compiling a shim with 428 wrappers in it", and that
+was the *opt-in* path. It is not what happens, because `Reach.link` drops the
+bindings nothing reachable calls and the shim comes back in parts for exactly
+that purpose. `sand.flan` links **110** wrappers, not 425 — `nm sand | grep -c
+flan_shim_`. A program that never draws still compiles no drawing wrapper.
+(`flan shim <file>` prints the unpruned view, so it says 427 and is not the
+number a build pays.)
+
+What is left is frontend work on 253 more declarations, and it is small:
+
+| cold build of `sand.flan`, object cache cleared | best of 3 |
+|---|---|
+| 425 declarations (committed bindings) | 2.16s |
+| 172 declarations (`generated.flan` moved aside) | 2.10s |
+
+**+65ms, about 3%, and cold only** — the object cache serves the shim after one
+build, and the redefinition path never recompiles C at all. Against it: the
+header read this removes was 60–90ms of a fresh session by the measurement
+above, and DISCUSS.md 6a measured it at 15.5ms on *every* redefinition, which is
+a 50% increase on the number the dev-loop lane exists to keep small. So for
+anyone who had the opt-in switched on this is a straight win, and for everyone
+else it is 65ms once per cold build in exchange for 253 bindings that were
+previously unreachable.
+
 Two bindings the config cannot express stay hand-written, and they are the
 reason `declare-c` remains the escape hatch: `LoadFontEx` and
 `LoadImageFromMemory` are bound `-raw` and wrapped by a Flan function of the

lib/cimport.ml

@@ -639,7 +639,8 @@ let of_dump ~env ~taken ~bound_syms ~config (d : dump) : imported =
        hidden :=
          (flan_name config f.csym,
           Printf.sprintf
-            "%s is excluded by the package's binding config, so no declaration              is generated for it" f.csym)
+            "%s is excluded by the package's binding config, so no \
+             declaration is generated for it" f.csym)
          :: !hidden)
     dropped;
   let groups = Hashtbl.create 512 in

test/test_acceptance.ml

@@ -802,23 +802,21 @@ let () =
        TextLength of "hello" is 5, which is only true if the generated wrapper
        NUL-terminated the copy.
 
-       Skipped without FLAN_RAYLIB_H, because the import is opt-in — a build
+       This used to be skipped without FLAN_RAYLIB_H, because the generated
-       needs libraylib linkable and not raylib-devel installed, and that is a
+       bindings only existed when a header was read. They are committed now —
-       property worth keeping. The importer's own table does not skip: it runs
+       vendor/raylib/generated.flan — so it runs on the same terms as every
-       against test/headers/sample.h, which is committed. *)
+       other raylib case here: libraylib linkable, and no raylib-devel. That is
-    (match Sys.getenv_opt "FLAN_RAYLIB_H" with
+       the change stated as a test rather than as a claim. If generated.flan
-     | Some h when Sys.file_exists h
+       were ever regenerated empty or stale, this is what would say so, and it
-                   && Sys.command "ldconfig -p 2>/dev/null | grep -q libraylib" = 0 ->
+       would say so on an ordinary machine rather than only on one with a
-       let out = "10\n5\n287454020\n17\n34\n51\n68\n" in
+       header exported. *)
-       outputs "raylib, bindings read from the header" "programs/raylib-imported.flan" out;
+    let out = "10\n5\n287454020\n17\n34\n51\n68\n" in
-       (* At -O0 too, for the reason the rest of the table is: every struct
+    outputs "raylib, bindings generated from the header" "programs/raylib-imported.flan" out;
-          here crosses as (addr v) on a local, which is the alloca mem2reg
+    (* At -O0 too, for the reason the rest of the table is: every struct
-          would launder before anyone noticed it was wrong. *)
+       here crosses as (addr v) on a local, which is the alloca mem2reg
-       outputs ~opt:"-O0" "raylib, bindings read from the header, -O0"
+       would launder before anyone noticed it was wrong. *)
-         "programs/raylib-imported.flan" out
+    outputs ~opt:"-O0" "raylib, bindings generated from the header, -O0"
-     | _ ->
+      "programs/raylib-imported.flan" out;
-       print_endline
-         "acceptance: skipping the imported-bindings case (FLAN_RAYLIB_H unset)");
 
     (* raylib's Image family, headless, and the strongest FFI case here: an
        Image is pixels in RAM, so raylib *computes* with it rather than