FindCUDA: Do not assume CMAKE_SYSTEM_PROCESSOR is set

CMAKE_SYSTEM_PROCESSOR is not guaranteed to be defined (per
http://www.cmake.org/Wiki/CMake_Cross_Compiling), and when cross
compiling where it happens to be undefined, this module was broken.

Reviewed-by: Rolf Eike Beer <[email protected]>

Modules/FindCUDA.cmake

@@ -613,7 +613,7 @@ endif()
 set(CUDA_VERSION_STRING "${CUDA_VERSION}")
 
 # Support for arm cross compilation with CUDA 5.5
-if(CUDA_VERSION VERSION_GREATER "5.0" AND CMAKE_CROSSCOMPILING AND ${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm" AND EXISTS "${CUDA_TOOLKIT_ROOT_DIR}/targets/armv7-linux-gnueabihf")
+if(CUDA_VERSION VERSION_GREATER "5.0" AND CMAKE_CROSSCOMPILING AND CMAKE_SYSTEM_PROCESSOR MATCHES "arm" AND EXISTS "${CUDA_TOOLKIT_ROOT_DIR}/targets/armv7-linux-gnueabihf")
   set(CUDA_TOOLKIT_TARGET_DIR "${CUDA_TOOLKIT_ROOT_DIR}/targets/armv7-linux-gnueabihf" CACHE PATH "Toolkit target location.")
 else()
   set(CUDA_TOOLKIT_TARGET_DIR "${CUDA_TOOLKIT_ROOT_DIR}" CACHE PATH "Toolkit target location.")
@@ -621,7 +621,7 @@ endif()
 mark_as_advanced(CUDA_TOOLKIT_TARGET_DIR)
 
 # Target CPU architecture
-if(CUDA_VERSION VERSION_GREATER "5.0" AND CMAKE_CROSSCOMPILING AND ${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")
+if(CUDA_VERSION VERSION_GREATER "5.0" AND CMAKE_CROSSCOMPILING AND CMAKE_SYSTEM_PROCESSOR MATCHES "arm")
   set(_cuda_target_cpu_arch_initial "ARM")
 else()
   set(_cuda_target_cpu_arch_initial "")