taskmgr: Cast to LPARAM the 4th argument passed to SendMessage.

Casting to long would truncate the pointers when compiling with MSVC
for Win64.
diff --git a/programs/taskmgr/taskmgr.c b/programs/taskmgr/taskmgr.c
index 8ba832e..b30ed8e 100644
--- a/programs/taskmgr/taskmgr.c
+++ b/programs/taskmgr/taskmgr.c
@@ -151,7 +151,7 @@
     nParts[0] = 100;
     nParts[1] = 210;
     nParts[2] = 400;
-    SendMessageW(hStatusWnd, SB_SETPARTS, 3, (long)nParts);
+    SendMessageW(hStatusWnd, SB_SETPARTS, 3, (LPARAM)nParts);
 
     /* Create tab pages */
     hTabWnd = GetDlgItem(hWnd, IDC_TAB);
@@ -518,7 +518,7 @@
 
     /* Update the status bar pane sizes */
     nParts = -1;
-    SendMessageW(hStatusWnd, SB_SETPARTS, 1, (long)&nParts);
+    SendMessageW(hStatusWnd, SB_SETPARTS, 1, (LPARAM)&nParts);
     bInMenuLoop = TRUE;
     SendMessageW(hStatusWnd, SB_SETTEXTW, 0, 0);
 }
@@ -538,7 +538,7 @@
     nParts[0] = 100;
     nParts[1] = 210;
     nParts[2] = rc.right;
-    SendMessageW(hStatusWnd, SB_SETPARTS, 3, (long)nParts);
+    SendMessageW(hStatusWnd, SB_SETPARTS, 3, (LPARAM)nParts);
     SendMessageW(hStatusWnd, SB_SETTEXT, 0, 0);
     wsprintfW(text, wszCPU_Usage, PerfDataGetProcessorUsage());
     SendMessageW(hStatusWnd, SB_SETTEXTW, 1, (LPARAM)text);