tests: Build correct sandbox configuration on 32bit

Currently sandbox configuration defautls to 64bit and there is no
automation for building 32bit sandbox on 32bit hosts.

Use _LP64 macro as heuristic for detecting 64bit targets.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index dad5583..b7598ca 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -22,6 +22,10 @@
 # Return y if the compiler supports <flag>, n otherwise
 cc-option = $(success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null)
 
+# $(cc-define,<macro>)
+# Return y if the compiler defines <macro>, n otherwise
+cc-define = $(success,$(CC) -dM -E -x c /dev/null | grep -q '^#define \<$(1)\>')
+
 # $(ld-option,<flag>)
 # Return y if the linker supports <flag>, n otherwise
 ld-option = $(success,$(LD) -v $(1))