kernel32: Use a longer wineboot timeout for the initial prefix creation.

dlls/kernel32/process.c

@@ -1079,9 +1079,11 @@ void CDECL __wine_kernel_init(void)
 
     if (boot_events[0])
     {
-        DWORD count = 1;
+        DWORD timeout = 30000, count = 1;
+
         if (boot_events[1]) count++;
-        if (WaitForMultipleObjects( count, boot_events, FALSE, 30000 ) == WAIT_TIMEOUT)
+        if (!got_environment) timeout = 300000;  /* initial prefix creation can take longer */
+        if (WaitForMultipleObjects( count, boot_events, FALSE, timeout ) == WAIT_TIMEOUT)
             ERR( "boot event wait timed out\n" );
         CloseHandle( boot_events[0] );
         if (boot_events[1]) CloseHandle( boot_events[1] );