all: initial support for LLVM 21

cgo/libclang.go

@@ -21,6 +21,10 @@ import (
 )
 
 /*
+// Hide a warning in LLVM 21 that doesn't apply to us (appears to be a side
+// effect of how CGo processes C header files).
+#cgo CFLAGS: -Wno-deprecated-declarations
+
 #include <clang-c/Index.h> // If this fails, libclang headers aren't available. Please take a look here: https://tinygo.org/docs/guides/build/
 #include <llvm/Config/llvm-config.h>
 #include <stdlib.h>

cgo/libclang_config_llvm20.go

@@ -1,4 +1,4 @@
-//go:build !byollvm && !llvm15 && !llvm16 && !llvm17 && !llvm18 && !llvm19
+//go:build !byollvm && llvm20
 
 package cgo
 

cgo/libclang_config_llvm21.go

@@ -0,0 +1,15 @@
+//go:build !byollvm && !llvm15 && !llvm16 && !llvm17 && !llvm18 && !llvm19 && !llvm20
+
+package cgo
+
+/*
+#cgo linux        CFLAGS:  -I/usr/include/llvm-21 -I/usr/include/llvm-c-21 -I/usr/lib/llvm-21/include
+#cgo darwin,amd64 CFLAGS:  -I/usr/local/opt/llvm@21/include
+#cgo darwin,arm64 CFLAGS:  -I/opt/homebrew/opt/llvm@21/include
+#cgo freebsd      CFLAGS:  -I/usr/local/llvm21/include
+#cgo linux        LDFLAGS: -L/usr/lib/llvm-21/lib -lclang
+#cgo darwin,amd64 LDFLAGS: -L/usr/local/opt/llvm@21/lib -lclang
+#cgo darwin,arm64 LDFLAGS: -L/opt/homebrew/opt/llvm@21/lib -lclang
+#cgo freebsd      LDFLAGS: -L/usr/local/llvm21/lib -lclang
+*/
+import "C"