tools: testing: allow importing arch headers in shared.mk

There is an arch/ tree under tools.  This contains some useful stuff, to
make that available, add it to the -I flags.  This requires $(SRCARCH),
which is provided by Makefile.arch, so include that..

There still aren't that many headers so also just smush all of them into
SHARED_DEPS instead of starting to do any header dependency hocus pocus.

Link: https://lkml.kernel.org/r/20250828-b4-vma-no-atomic-h-v2-2-02d146a58ed2@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Cc: Jann Horn <jannh@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/shared/shared.mk

@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
+include ../../scripts/Makefile.arch
 
-CFLAGS += -I../shared -I. -I../../include -I../../../lib -g -Og -Wall \
+CFLAGS += -I../shared -I. -I../../include -I../../arch/$(SRCARCH)/include \
+	  -I../../../lib -g -Og -Wall \
 	  -D_LGPL_SOURCE -fsanitize=address -fsanitize=undefined
 LDFLAGS += -fsanitize=address -fsanitize=undefined
 LDLIBS += -lpthread -lurcu
@@ -11,6 +13,7 @@ SHARED_DEPS = Makefile ../shared/shared.mk ../shared/*.h generated/map-shift.h \
 	generated/bit-length.h generated/autoconf.h \
 	../../include/linux/*.h \
 	../../include/asm/*.h \
+	../../arch/$(SRCARCH)/include/asm/*.h \
 	../../../include/linux/xarray.h \
 	../../../include/linux/maple_tree.h \
 	../../../include/linux/radix-tree.h \