refactor(cl):allow empty lib command

Author: luoliwoshang

cl/internal/convert/_testdata/withoutlib/conf/llcppg.cfg

@@ -0,0 +1,5 @@
+{
+  "name": "withoutlib",
+  "include": ["temp.h"],
+  "cplusplus":false
+}

cl/internal/convert/_testdata/withoutlib/gogensig.expect

@@ -0,0 +1,20 @@
+===== temp.go =====
+package withoutlib
+
+import (
+	"github.com/goplus/lib/c"
+	_ "unsafe"
+)
+
+type Temp struct {
+	A c.Int
+	B c.Int
+}
+
+===== withoutlib_autogen_link.go =====
+package withoutlib
+
+import _ "github.com/goplus/lib/c"
+
+===== llcppg.pub =====
+temp Temp

cl/internal/convert/_testdata/withoutlib/hfile/temp.h

@@ -0,0 +1,4 @@
+typedef struct temp {
+    int a;
+    int b;
+} temp;

cl/internal/convert/package.go

@@ -46,10 +46,13 @@ type Package struct {
 
 type PackageConfig struct {
 	PkgBase
-	Name       string // current package name
-	OutputDir  string
-	GenConf    *gogen.Config
-	LibCommand string // use to gen link command like $(pkg-config --libs xxx)
+	Name      string // current package name
+	OutputDir string
+	GenConf   *gogen.Config
+
+	// use to gen link command like $(pkg-config --libs xxx)
+	// if have this field,will generate a const named LLGoPackage,and it's not necessary
+	LibCommand string
 }
 
 // When creating a new package for conversion, a Go file named after the package is generated by default.
@@ -92,10 +95,14 @@ func NewPackage(pnc nc.NodeConverter, config *PackageConfig) (*Package, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to init deps: %w", err)
 	}
-	err = p.initLink()
-	if err != nil {
-		return nil, fmt.Errorf("failed to init link: %w", err)
+
+	// allow have not lib command
+	if p.conf.LibCommand != "" {
+		if err := p.initLink(p.conf.LibCommand); err != nil {
+			return nil, fmt.Errorf("failed to init link: %w", err)
+		}
 	}
+
 	p.markUseDeps(pkgManager)
 	p.cvt = NewConv(p.p, p.p.Types, pnc, p.lookupType)
 	return p, nil
@@ -133,16 +140,6 @@ func (p *Package) setGoFile(goFile string) {
 	p.p.Unsafe().MarkForceUsed(p.p)
 }
 
-// todo(zzy):refine logic
-func (p *Package) linkLib(lib string) error {
-	if lib == "" {
-		return fmt.Errorf("empty lib name")
-	}
-	linkString := fmt.Sprintf("link: %s;", lib)
-	p.p.CB().NewConstStart(types.Typ[types.String], "LLGoPackage").Val(linkString).EndInit(1)
-	return nil
-}
-
 func (p *Package) newReceiver(typ *ast.FuncType) (*types.Var, error) {
 	recvField := typ.Params.List[0]
 	recvType, err := p.ToType(recvField.Type)
@@ -714,17 +711,14 @@ func (p *Package) autoLinkFile() string {
 	return p.conf.Name + "_autogen_link.go"
 }
 
-func (p *Package) initLink() error {
-	fileName := p.autoLinkFile()
-	_, err := p.p.SetCurFile(fileName, true)
+func (p *Package) initLink(lib string) (err error) {
+	_, err = p.p.SetCurFile(p.autoLinkFile(), true)
 	if err != nil {
 		return fmt.Errorf("failed to set current file: %w", err)
 	}
-	err = p.linkLib(p.conf.LibCommand)
-	if err != nil {
-		return err
-	}
-	return nil
+	linkString := fmt.Sprintf("link: %s;", lib)
+	p.p.CB().NewConstStart(types.Typ[types.String], "LLGoPackage").Val(linkString).EndInit(1)
+	return
 }
 
 func (p *Package) deferTypeBuild() error {