cmake: Build CUDA 6.5 object without C++11

CUDA 7.0 is the first version that supports C++11.

Though linking C++11 objects with non-C++11 ones is problematic.

Author: xlz

CMakeLists.txt

@@ -342,10 +342,16 @@ IF(ENABLE_CUDA)
     IF(NOT MSVC)
       SET(CUDA_FLAGS "${CUDA_FLAGS} -Xcompiler -fPIC")
     ENDIF()
+
+    SET(OLD_CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+    IF(CUDA_VERION VERSION_LESS 7.0)
+      STRING(REGEX REPLACE "-std=c\\+\\+.." "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+    ENDIF()
     CUDA_COMPILE(CUDA_OBJECTS
       src/cuda_depth_packet_processor.cu
       OPTIONS ${CUDA_FLAGS}
     )
+    SET(CMAKE_CXX_FLAGS "${OLD_CMAKE_CXX_FLAGS}")
 
     INCLUDE_DIRECTORIES(${CUDA_INCLUDE_DIRS})
 

src/cuda_depth_packet_processor.cu

@@ -85,6 +85,9 @@ __constant__ static float MAX_DEPTH;
 #define max(x, y) fmaxf(x, y)
 #define min(x, y) fminf(x, y)
 #define M_PI_F CUDART_PI_F
+#ifndef M_PI
+#define M_PI CUDART_PI
+#endif
 
 typedef unsigned char uchar;