make: build zy with the llvm backend when an llvm with headers is found; NOLLVM=1 turns it off

1 files changed, 7 insertions, 3 deletions

diff --git a/TODO.md b/TODO.md
index bba2ff7..e76b7c3 100644
--- a/TODO.md
+++ b/TODO.md
@@ -241,9 +241,13 @@ the reasoning behind the open items survives the session.
   translation validation of each compile over proving the compiler whole.
 - native code: the hand-written jit exists for arm64 and (phase 1, no o3
   regions or inlined enhancements yet) x86-64 linux; the llvm backend
-  (`-DZYLLVM`) is the portable native tier but the default build leaves it
-  out. cheap win: build the llvm core by default whenever `llvm-config` is
-  found. the x86-64 port of the hand-written jit is worth it for compile
+  (`-DZYLLVM`) is the portable native tier, and `make` now puts it in `zy`
+  whenever `llvm-config` or `llvm-config-19` with headers is found
+  (`NOLLVM=1` turns it off; without llvm the build prints a note and goes on).
+  checked on x86-64 with llvm 19: the fixpoint with llvm, without llvm on
+  `PATH`, and with `NOLLVM=1`, and `tests/test.sh --section llvm` (149 ok).
+  open: `-DZYLLVM` replaces the x86-64 jit, so the default x86-64 `zy` now
+  uses llvm rather than the hand-written jit; decide whether that is wanted. the x86-64 port of the hand-written jit is worth it for compile
   latency (microseconds per block against milliseconds for llvm), which
   matters for short programs and the language server.