get rid of XFree86LOADER, XFree86Server, XFree86Module, and IN_MODULE

Get rid of almost all uses of these definitions.  They're still defined for
delinquent out-of-tree drivers, and also for the Mesa build.  As well as
for miinitext.c.  But largely gone.

hw/xfree86/os-support/linux/int10/linux.c

@@ -18,12 +18,6 @@
 #else
 #define DEV_MEM "/dev/mem"
 #endif
-#ifndef XFree86LOADER
-#include <sys/mman.h>
-#ifndef MAP_FAILED
-#define MAP_FAILED ((void *)-1)
-#endif
-#endif
 #define ALLOC_ENTRIES(x) ((V_RAM / x) - 1)
 #define SHMERRORPTR (pointer)(-1)