BUILD: Fixing linux build due to incorrect syntax when variable is empty

Author: adamrankin

CMakeLists.txt

@@ -172,7 +172,7 @@ ENDIF()
 
 SET(PHIDGET_SPATIAL_BASE_DIR ${PLUSLIB_TOOLS_DIR}/Phidget/Phidget22)
 SET(PHIDGET_SPATIAL_INCLUDE_DIR ${PHIDGET_SPATIAL_BASE_DIR} CACHE PATH "Path to the Phidget Spatial include folder" FORCE )
-IF(MSVC AND ${CMAKE_VS_PLATFORM_NAME} MATCHES "x64")
+IF(MSVC AND "${CMAKE_VS_PLATFORM_NAME}" MATCHES "x64")
   SET(PHIDGET_SPATIAL_LIB_DIR ${PHIDGET_SPATIAL_BASE_DIR}/x64 CACHE PATH "Path to the Phidget Spatial 64-bit lib folder" FORCE )
   SET(PHIDGET_SPATIAL_BINARY_DIR ${PHIDGET_SPATIAL_BASE_DIR}/x64 CACHE PATH "Path to the Phidget Spatial 64-bit dll folder" FORCE )
 ELSE()
@@ -190,7 +190,7 @@ ENDIF()
 
 SET(EPIPHAN_SDK_BASE_DIR ${PLUSLIB_TOOLS_DIR}/Epiphan)
 SET(EPIPHAN_INCLUDE_DIR ${EPIPHAN_SDK_BASE_DIR} CACHE PATH "Path to the Epiphan SDK include directory." FORCE )
-IF(MSVC AND ${CMAKE_VS_PLATFORM_NAME} MATCHES "x64")
+IF(MSVC AND "${CMAKE_VS_PLATFORM_NAME}" MATCHES "x64")
   SET(EPIPHAN_BINARY_DIR ${EPIPHAN_SDK_BASE_DIR}/x64 CACHE PATH "Directory containing Epiphan shared library file." FORCE)
   SET(EPIPHAN_LIB_DIR ${EPIPHAN_SDK_BASE_DIR}/x64 CACHE PATH "Directory containing Epiphan static library file." FORCE)
 ELSE()