[PATCH] Fix SMP compilation with 'multiquad' driver

The 2.4.18pre10 kernel, like many if its predecessors, can't compile
the multiquad driver in an SMP kernel (maybe only as a module; it's
been a long time since I wrote this fix).  Here's a patch.

arch/i386/boot/compressed/misc.c

@@ -125,7 +125,7 @@ static int vidport;
 static int lines, cols;
 
 #ifdef CONFIG_MULTIQUAD
-static void *xquad_portio = NULL;
+static void * const xquad_portio = NULL;
 #endif
 
 #include "../../../../lib/inflate.c"

arch/i386/kernel/i386_ksyms.c

@@ -176,3 +176,7 @@ extern int is_sony_vaio_laptop;
 EXPORT_SYMBOL(is_sony_vaio_laptop);
 
 EXPORT_SYMBOL(__PAGE_KERNEL);
+
+#ifdef CONFIG_MULTIQUAD
+EXPORT_SYMBOL(xquad_portio);
+#endif

arch/i386/kernel/smpboot.c

@@ -1011,7 +1011,7 @@ extern int prof_counter[NR_CPUS];
 
 static int boot_cpu_logical_apicid;
 /* Where the IO area was mapped on multiquad, always 0 otherwise */
-void *xquad_portio = NULL;
+void *xquad_portio;
 
 int cpu_sibling_map[NR_CPUS] __cacheline_aligned;