diff --git a/Sources/BuildScripts/XCFrameworkBuild/base.swift b/Sources/BuildScripts/XCFrameworkBuild/base.swift
--- a/Sources/BuildScripts/XCFrameworkBuild/base.swift
+++ b/Sources/BuildScripts/XCFrameworkBuild/base.swift
@@ -1176,6 +1176,14 @@ enum Utility {
         if !environment.keys.contains("PATH") {
             environment["PATH"] = BaseBuild.defaultPath
         }
+        // Conflux：透传 DEVELOPER_DIR 与 SDKROOT。环境在这里被整体替换，不透传的话 xcrun 只认
+        // xcode-select，调用方指定的 Xcode 会被静默换成机器默认那一版；configure 里不带 -isysroot
+        // 的宿主编译器探测（例如 gmp 的 build system compiler）也会落到 CommandLineTools 的 SDK。
+        for key in ["DEVELOPER_DIR", "SDKROOT"] where environment[key] == nil {
+            if let value = ProcessInfo.processInfo.environment[key] {
+                environment[key] = value
+            }
+        }
         task.environment = environment
 
         var outputFileHandle: FileHandle?