luajit: fix aarch64 cross-compile

Unlike CMAKE_SYSTEM_PROCESSOR which identifies aarch64
as a valid architecture, luajit does not recognize it.
luajit defines aarch64 as arm64.

Signed-off-by: Jugurtha BELKALEM <jugurtha.belkalem@smile.fr>
Signed-off-by: Romain Naour <romain.naour@smile.fr>

src/lua/CMakeLists.txt

@@ -13,9 +13,15 @@ if (LUAJIT_LIBRARIES AND LUAJIT)
 		DEPENDS ${SRC_LUA} ${CMAKE_CURRENT_SOURCE_DIR}/squishy
 	)
 
+	if (CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64")
+		SET (LUAJIT_TARGET_ARCH arm64)
+	else()
+		SET (LUAJIT_TARGET_ARCH ${CMAKE_SYSTEM_PROCESSOR})
+	endif()
+
 	ADD_CUSTOM_COMMAND(
 		OUTPUT bcc.o
-		COMMAND ${LUAJIT} -bg bcc.lua bcc.o
+		COMMAND ${LUAJIT} -bg bcc.lua -a ${LUAJIT_TARGET_ARCH} bcc.o
 		DEPENDS bcc.lua
 	)