cmake: ARCH_ID fixes for cross compilation

CMakeLists.txt

@@ -113,6 +113,9 @@ string(TOLOWER ${CMAKE_BUILD_TYPE} CMAKE_BUILD_TYPE_LOWER)
 # to identify the target architecture, to direct logic in this cmake script.
 # Since ARCH is a cached variable, it will not be set on first cmake invocation.
 if (NOT ARCH OR ARCH STREQUAL "" OR ARCH STREQUAL "native" OR ARCH STREQUAL "default")
+  if(CMAKE_SYSTEM_PROCESSOR STREQUAL "")
+    set(CMAKE_SYSTEM_PROCESSOR ${CMAKE_HOST_SYSTEM_PROCESSOR})
+  endif()
   set(ARCH_ID "${CMAKE_SYSTEM_PROCESSOR}")
 else()
   set(ARCH_ID "${ARCH}")

contrib/depends/toolchain.cmake.in

@@ -41,6 +41,8 @@ set (CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER) # Find programs on host
 set (CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY) # Find libs in target
 set (CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY) # Find includes in target
 
+set(CMAKE_SYSTEM_PROCESSOR ${CMAKE_HOST_SYSTEM_PROCESSOR} CACHE STRING "" FORCE)
+
 # specify the cross compiler to be used. Darwin uses clang provided by the SDK.
 if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   SET(CMAKE_C_COMPILER @prefix@/native/bin/clang)
@@ -85,6 +87,11 @@ endif()
 
 if(ARCHITECTURE STREQUAL "i686" AND CMAKE_SYSTEM_NAME STREQUAL "Linux")
   SET(LINUX_32 ON)
+  SET(ARCH_ID "i386")
+endif()
+
+if(ARCHITECTURE STREQUAL "x86_64" AND CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  SET(ARCH_ID "x86_64")
 endif()
 
 #Create a new global cmake flag that indicates building with depends