Fix occurrence of startswith_insensitive osx

Author: mcbarton

lib/Interpreter/DynamicLibraryManager.cpp

@@ -302,7 +302,7 @@ namespace Cpp {
     // Subst all known linker variables ($origin, @rpath, etc.)
 #ifdef __APPLE__
     // On MacOS @rpath is preplaced by all paths in RPATH one by one.
-    if (libStem.startswith_insensitive("@rpath")) {
+    if (libStem.starts_with_insensitive("@rpath")) {
       for (auto& P : RPath) {
         std::string result = substFront(libStem, "@rpath", P);
         if (isSharedLibrary(result))