AppServerLink: Use a mutex.

X512 pointed out that ServerLink is inherited by PortLink which is
used by all windows, so the original change had the unintended effect
of allocating another semaphore for every window, which isn't wanted.
So, just use a static mutex here also.

src/kits/app/AppServerLink.cpp

@@ -13,6 +13,8 @@
 #include <ApplicationPrivate.h>
 #include <AppServerLink.h>
 
+#include <locks.h>
+
 
 /**	AppServerLink provides proxied access to the application's
  *	connection with the app_server.
@@ -22,13 +24,17 @@
  */
 
 
+static mutex sLock = MUTEX_INITIALIZER("AppServerLink_sLock");
+
+
 namespace BPrivate {
 
 AppServerLink::AppServerLink()
 {
+	mutex_lock(&sLock);
+
 	// if there is no be_app, we can't do a whole lot, anyway
 	if (be_app != NULL) {
-		BApplication::Private::ServerLink()->Lock();
 		fReceiver = &BApplication::Private::ServerLink()->Receiver();
 		fSender = &BApplication::Private::ServerLink()->Sender();
 	} else {
@@ -39,7 +45,7 @@ AppServerLink::AppServerLink()
 
 AppServerLink::~AppServerLink()
 {
-	BApplication::Private::ServerLink()->Unlock();
+	mutex_unlock(&sLock);
 }
 
 }	// namespace BPrivate

src/kits/app/ServerLink.cpp

@@ -24,8 +24,6 @@ namespace BPrivate {
 
 
 ServerLink::ServerLink()
-	:
-	BLocker()
 {
 }