fix: check PKG_CONFIG_PATH

Author: MeteorsLiu

Diff for: compiler/internal/build/build.go

@@ -318,7 +318,9 @@ func setDepsPC(ctx *context, pkg *packages.Package) {
 	}
 
 	if len(pcDir) > 0 {
-		pcDir = append(pcDir, os.Getenv("PKG_CONFIG_PATH"))
+		if pkgPath, ok := os.LookupEnv("PKG_CONFIG_PATH"); ok {
+			pcDir = append(pcDir, pkgPath)
+		}
 		os.Setenv("PKG_CONFIG_PATH", strings.Join(pcDir, ":"))
 	}
 }

Diff for: compiler/internal/pc/env.go

@@ -6,14 +6,14 @@ import (
 	"os/exec"
 )
 
-func AppendPCPath(path string) string {
+func appendPCPath(path string) string {
 	if env, ok := os.LookupEnv("PKG_CONFIG_PATH"); ok {
 		return path + ":" + env
 	}
 	return path
 }
 
 func SetPath(cmd *exec.Cmd, path string) {
-	pcPath := fmt.Sprintf("PKG_CONFIG_PATH=%s", AppendPCPath(path))
+	pcPath := fmt.Sprintf("PKG_CONFIG_PATH=%s", appendPCPath(path))
 	cmd.Env = append(os.Environ(), pcPath)
 }