Revert "Split adb_main.cpp into client and daemon."

This reverts commit cf07494ac2a101c3afbe23a7d85121553f586cf7.
diff --git a/adb/usb_osx.cpp b/adb/usb_osx.cpp
index af65130..0d0b3ad 100644
--- a/adb/usb_osx.cpp
+++ b/adb/usb_osx.cpp
@@ -401,18 +401,11 @@
     return NULL;
 }
 
-static void usb_cleanup() {
-    DBG("usb_cleanup\n");
-    close_usb_devices();
-    if (currentRunLoop)
-        CFRunLoopStop(currentRunLoop);
-}
 
+static int initialized = 0;
 void usb_init() {
-    static bool initialized = false;
-    if (!initialized) {
-        atexit(usb_cleanup);
-
+    if (!initialized)
+    {
         adb_mutex_init(&start_lock, NULL);
         adb_cond_init(&start_cond, NULL);
 
@@ -428,10 +421,18 @@
         adb_mutex_destroy(&start_lock);
         adb_cond_destroy(&start_cond);
 
-        initialized = true;
+        initialized = 1;
     }
 }
 
+void usb_cleanup()
+{
+    DBG("usb_cleanup\n");
+    close_usb_devices();
+    if (currentRunLoop)
+        CFRunLoopStop(currentRunLoop);
+}
+
 int usb_write(usb_handle *handle, const void *buf, int len)
 {
     IOReturn    result;