all: add LLVM 22 support

Builder:
- Update clang.cpp for LLVM 22 API changes: DiagnosticOptions is no
  longer ref-counted, TextDiagnosticPrinter and DiagnosticsEngine take
  references instead of pointers, createDiagnostics() signature changed.
- Update cc1as.cpp: clang/Driver/Options.h moved to
  clang/Options/Options.h, namespace changed from clang::driver::options
  to clang::options, MCInstPrinter now passed as unique_ptr.
- Add new LLVM 22 libraries to GNUmakefile: clangAnalysisLifetimeSafety,
  clangOptions, LLVMDTLTO, and dtlto component.
- Add llvm22 build tag to all build/test commands.

CGo:
- Handle CXType_Unexposed in libclang.go by resolving via canonical
  type. LLVM 22 reports builtin type aliases (e.g. __size_t) as
  Unexposed instead of Typedef.
- Always make C typedefs into Go type aliases. LLVM 22 changed
  getTypedefDeclUnderlyingType to return CXType_Enum directly instead
  of wrapping in an elaborated type.

Compileopts:
- Add build-tag-guarded ClangTriple() to substitute wasm32-unknown-wasi
  with wasm32-unknown-wasip1 for LLVM 22 (deprecated triple).
- Add build-tag-guarded patchFeatures() to map renamed Xtensa features
  (atomctl, memctl, timerint, esp32s3) for LLVM 22.

Targets:
- Remove -zca from RISC-V target feature strings (esp32c3, esp32c6,
  fe310, k210, riscv-qemu, tkey). LLVM 22 now implies +zca from +c.
- Remove -zcd from k210. LLVM 22 now implies +zcd from +c,+d.

Tests:
- Change TestClangAttributes to check individual feature flags instead
  of exact string match, allowing new LLVM features without failures.
- Update TestBinarySize expected values for LLVM 22 codegen.

Signed-off-by: deadprogram <ron@hybridgroup.com>

builder/sizes_test.go

@@ -42,9 +42,9 @@ func TestBinarySize(t *testing.T) {
 	// This is a small number of very diverse targets that we want to test.
 	tests := []sizeTest{
 		// microcontrollers
-		{"hifive1b", "examples/echo", 3769, 307, 0, 2260},
-		{"microbit", "examples/serial", 2828, 368, 8, 2256},
-		{"wioterminal", "examples/pininterrupt", 8065, 1663, 132, 7488},
+		{"hifive1b", "examples/echo", 4277, 307, 0, 2260},
+		{"microbit", "examples/serial", 2836, 368, 8, 2256},
+		{"wioterminal", "examples/pininterrupt", 8013, 1663, 132, 7488},
 
 		// TODO: also check wasm. Right now this is difficult, because
 		// wasm binaries are run through wasm-opt and therefore the