vendors/ is a third-party namespace (stb_image, kb_text_shape, etc.);
test fixtures don't belong there. The .c/.h companion files for the
Phase-0 FFI baselines now sit alongside the .sx that drives them in
examples/, with matching basenames:
examples/ffi-01-primitives.{sx,c,h} <- was vendors/ffi_primitives/
examples/ffi-02-small-struct.{sx,c,h} <- was vendors/ffi_structs/
examples/ffi-03-large-struct.{sx,c,h} <- was vendors/ffi_large_struct/
examples/ffi-04-fp-struct.{sx,c,h} <- was vendors/ffi_fp_struct/
examples/ffi-05-string-args.{sx,c,h} <- was vendors/ffi_strings/
examples/ffi-06-callback.{sx,c,h} <- was vendors/ffi_callback/
examples/101-ffi-medium-struct.{sx,c} <- was vendors/ffi_medium_struct/
`#source` / `#include` paths in the .sx files become bare filenames
(no prefix) since imports.zig's base_dir resolution finds them
relative to the importing .sx file's directory.
`library/vendors/sx_ffi_resolve_test/` stays put — that one's the
whole point: regression coverage for the stdlib-search branch of
the resolution chain, so it must live where ONLY that branch can
find it.
94/94 regression tests pass.
93/93 regression tests pass (+ffi-06-callback).
Mirrors the `app->onInputEvent` install pattern from
library/modules/platform/android.sx:
1. (s32) -> s32 — single primitive arg/return
2. (*void, s32) -> s32 — opaque ctx pointer + value
(the onInputEvent shape)
Side effects via two file-level globals so the test observes both
the return value AND state mutation across multiple calls:
- g_callback_hits = N proves the callback fired N times.
- g_callback_sum = sum of args proves each individual call landed
with the correct value.
The ctx-pointer variant casts `*void` back to `*s32` inside the
callback and reads through it (`p.*`), proving the pointer survives
the round-trip with no aliasing weirdness.
