Use HAXELIB_RUN env instead of modifying run

src/haxelib/client/Main.hx

@@ -157,6 +157,10 @@ class Main {
 	{
 		args = Sys.args();
 
+		if (Sys.getEnv("HAXELIB_RUN") == "1") {
+			Sys.setCwd(args.pop());
+		}
+
 		commands = new List();
 		addCommand("install", install, "install a given library, or all libraries from a hxml file", Basic);
 		addCommand("update", update, "update a single library (if given) or all installed libraries", Basic);
@@ -348,18 +352,16 @@ class Main {
 			}
 		}
 
-		if (!settings.safe && FileSystem.exists(getRepository() + "haxelib_client")) {
+		if ((!settings.safe && Sys.getEnv("HAXELIB_RUN") != "1") && FileSystem.exists(getRepository() + "haxelib_client")) {
 			var old_argcur = argcur;
 			argcur = 0; // send all arguments
-			args.unshift("--safe");
 
 			try {
-				doRun("haxelib_client", null, false);
+				doRun("haxelib_client", null);
 			} catch (e:String) {
 				if (e.startsWith("Library haxelib_client version ") && e.endsWith(" does not have a run script")) {
 					// old version of haxelib_client without run script, ignore
 					argcur = old_argcur;
-					args.shift();
 				} else {
 					throw e;
 				}
@@ -1374,7 +1376,7 @@ class Main {
 		doRun(temp[0], temp[1]);
 	}
 
-	function doRun( project:String, version:String, changeDir=true ) {
+	function doRun( project:String, version:String ) {
 		var rep = getRepository();
 		var pdir = rep + Data.safe(project);
 		if( !FileSystem.exists(pdir) )
@@ -1391,10 +1393,8 @@ class Main {
 			catch (e:Dynamic)
 				throw 'Error parsing haxelib.json for $project@$version: $e';
 
-		if (changeDir) {
-			args.push(Sys.getCwd());
-			Sys.setCwd(vdir);
-		}
+		args.push(Sys.getCwd());
+		Sys.setCwd(vdir);
 
 		var callArgs =
 			if (infos.main == null) {