internal/cl:include llvm-config --cflags to find libunwind.h

internal/crosscompile/cosscompile.go

@@ -6,9 +6,11 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 
 	"github.com/goplus/llgo/internal/env"
 	"github.com/goplus/llgo/internal/xtool/llvm"
+	envllvm "github.com/goplus/llgo/xtool/env/llvm"
 )
 
 type Export struct {
@@ -66,6 +68,10 @@ func Use(goos, goarch string, wasiThreads, changeRpath bool) (export Export, err
 				"-latomic",
 				"-lpthread", // libpthread is built-in since glibc 2.34 (2021-08-01); we need to support earlier versions.
 			)
+			llvmEnv := envllvm.New("")
+			if cflags := llvmEnv.Cflags(); cflags != "" {
+				export.CFLAGS = append(export.CFLAGS, strings.Fields(cflags)...)
+			}
 		}
 		return
 	}

xtool/env/llvm/llvm.go

@@ -50,6 +50,7 @@ func defaultLLVMConfigBin() string {
 // Env represents an LLVM installation.
 type Env struct {
 	binDir string
+	cflags string
 }
 
 // New creates a new [Env] instance.
@@ -62,7 +63,12 @@ func New(llvmConfigBin string) *Env {
 	// executables are assumed to be in PATH.
 	binDir, _ := exec.Command(llvmConfigBin, "--bindir").Output()
 
-	e := &Env{binDir: strings.TrimSpace(string(binDir))}
+	cflags, _ := exec.Command(llvmConfigBin, "--cflags").Output()
+
+	e := &Env{
+		binDir: strings.TrimSpace(string(binDir)),
+		cflags: strings.TrimSpace(string(cflags)),
+	}
 	return e
 }
 
@@ -70,6 +76,8 @@ func New(llvmConfigBin string) *Env {
 // means LLVM executables are assumed to be in PATH.
 func (e *Env) BinDir() string { return e.binDir }
 
+func (e *Env) Cflags() string { return e.cflags }
+
 // Clang returns a new [clang.Cmd] instance.
 func (e *Env) Clang() *clang.Cmd {
 	bin := filepath.Join(e.BinDir(), "clang++")