Fix current working directory default value

This commit fixes the issue when `cwd` is empty and is passed to `Runtime.getRuntime().exec(progArray, env, new File(cwd));`, it raises the `No such file or directory` exceptions when targeting sdk `29`.

Author: agnostic-apollo

app/src/main/java/com/termux/app/BackgroundJob.java

@@ -36,7 +36,7 @@ public BackgroundJob(String cwd, String fileToExecute, final String[] args, fina
 
     public BackgroundJob(String cwd, String fileToExecute, final String[] args, final TermuxService service, PendingIntent pendingIntent) {
         String[] env = buildEnvironment(false, cwd);
-        if (cwd == null) cwd = TermuxService.HOME_PATH;
+        if (cwd == null || cwd.isEmpty()) cwd = TermuxService.HOME_PATH;
 
         final String[] progArray = setupProcessArgs(fileToExecute, args);
         final String processDescription = Arrays.toString(progArray);
@@ -136,7 +136,7 @@ private static void addToEnvIfPresent(List<String> environment, String name) {
     static String[] buildEnvironment(boolean failSafe, String cwd) {
         new File(TermuxService.HOME_PATH).mkdirs();
 
-        if (cwd == null) cwd = TermuxService.HOME_PATH;
+        if (cwd == null || cwd.isEmpty()) cwd = TermuxService.HOME_PATH;
 
         List<String> environment = new ArrayList<>();
 

app/src/main/java/com/termux/app/TermuxService.java

@@ -282,7 +282,7 @@ public List<TerminalSession> getSessions() {
     TerminalSession createTermSession(String executablePath, String[] arguments, String cwd, boolean failSafe) {
         new File(HOME_PATH).mkdirs();
 
-        if (cwd == null) cwd = HOME_PATH;
+        if (cwd == null || cwd.isEmpty()) cwd = HOME_PATH;
 
         String[] env = BackgroundJob.buildEnvironment(failSafe, cwd);
         boolean isLoginShell = false;