sqlite is part of the program: #import c unit replaces the Makefile cc build

src/db/sqlite.sx declares the vendored amalgamation as a named
'#import c' unit (pinned defines + -O2 + #source); every #foreign
binding resolves against it with UNPREFIXED sqlite3_* names. sx
compiles the unit through its content-addressed object cache — once
per checkout — links the objects into 'sx build' binaries, and loads
them as a priority symbol target under 'sx run', so the OS libsqlite3
can never shadow the vendored copy (the version pin in sqlite_smoke
proves it).

Retired: the Makefile vendor targets (cc -> .a + jit/.dylib), the
GENERATED dist_sqlite3_* rename.h (the JIT no longer resolves
program-owned symbols through the process images, so the rename's
reason is gone), and the -L plumbing in make build + tests/run.sh.
make test 22/22; otool -L build/dist carries no libsqlite3.

tests/run.sh

@@ -8,15 +8,14 @@
 #
 # Locate the compiler via SX (overridable); defaults to the sibling sx repo.
 #
-# `-L build/vendor/jit` lets the JIT dlopen the VENDORED libsqlite3.dylib
-# (built by `make build`) instead of falling back to the OS copy — the
-# version assert in tests/sqlite_smoke.sx depends on it.
+# The vendored SQLite needs no flags here: src/db/sqlite.sx declares it
+# as a `#import c` unit, so `sx run` compiles (cached) and loads it as a
+# priority symbol target — the version assert in tests/sqlite_smoke.sx
+# proves the OS copy never shadows it.
 set -u
 
 SX="${SX:-/Users/agra/projects/sx/zig-out/bin/sx}"
 TESTS_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
-REPO_DIR=$(CDPATH= cd -- "$TESTS_DIR/.." && pwd)
-SX_RUN_FLAGS="-L $REPO_DIR/build/vendor/jit"
 
 pass=0
 fail=0
@@ -26,7 +25,7 @@ fail=0
 # pass/fail counters survive).
 for t in $(find "$TESTS_DIR" -name '*.sx' -type f | sort); do
     name=${t#"$TESTS_DIR"/}
-    if "$SX" run "$t" $SX_RUN_FLAGS >/dev/null 2>&1; then
+    if "$SX" run "$t" >/dev/null 2>&1; then
         printf '  %-44s ok\n' "$name"
         pass=$((pass + 1))
     else