[build] Add support for local configuration files

Include config/local/$file in config/$file where it makes sense and
create empty local configs during build if not present.

Modified-by: Michael Brown <mcb30@etherboot.org>
Signed-off-by: Michael Brown <mcb30@etherboot.org>

src/config/console.h

@@ -20,4 +20,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 //#define	CONSOLE_BTEXT		/* Who knows what this does? */
 //#define	CONSOLE_PC_KBD		/* Direct access to PC keyboard */
 
+#include <config/local/console.h>
+
 #endif /* CONFIG_CONSOLE_H */

src/config/general.h

@@ -145,4 +145,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #undef	GDBUDP			/* Remote GDB debugging over UDP
 				 * (both may be set) */
 
+#include <config/local/general.h>
+
 #endif /* CONFIG_GENERAL_H */

src/config/ioapi.h

@@ -14,4 +14,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 //#undef	PCIAPI_PCBIOS		/* Access via PCI BIOS */
 //#define	PCIAPI_DIRECT		/* Direct access via Type 1 accesses */
 
+#include <config/local/ioapi.h>
+
 #endif /* CONFIG_IOAPI_H */

src/config/isa.h

@@ -12,4 +12,6 @@
 #undef	ISA_PROBE_ADDRS		/* e.g. 0x200, 0x300 */
 #undef	ISA_PROBE_ONLY		/* Do not probe any other addresses */
 
+#include <config/local/isa.h>
+
 #endif /* CONFIG_ISA_H */

src/config/local/.gitignore

@@ -0,0 +1 @@
+*

src/config/nap.h

@@ -14,4 +14,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 //#undef		NAP_PCBIOS
 //#define		NAP_NULL
 
+#include <config/local/nap.h>
+
 #endif /* CONFIG_NAP_H */

src/config/serial.h

@@ -32,4 +32,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define	COMSTOP		1		/* Stop bits */
 #endif
 
+#include <config/local/serial.h>
+
 #endif /* CONFIG_SERIAL_H */

src/config/timer.h

@@ -14,4 +14,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 //#undef		TIMER_PCBIOS
 //#define		TIMER_RDTSC
 
+#include <config/local/timer.h>
+
 #endif /* CONFIG_TIMER_H */

src/config/umalloc.h

@@ -11,4 +11,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <config/defaults.h>
 
+#include <config/local/umalloc.h>
+
 #endif /* CONFIG_UMALLOC_H */