Merge pull request #308 from AxisRay/master

Bugfix:function setenv() and unsetenv() are invalid on windows AND no variable prefix set for WIN32 in CMakeLists

CMakeLists.txt

@@ -177,6 +177,7 @@ IF(WIN32)
   GET_CURRENT_YEAR(CURRENT_YEAR)
   MESSAGE("Year for copyright is " ${CURRENT_YEAR})
 
+  SET(prefix ${CMAKE_INSTALL_PREFIX})
   SET(RC_COMMENT "${PACKAGE_NAME} library")
   SET(RC_INTERNAL_NAME "${PACKAGE_NAME} ${WIN32_MODE}")
   SET(RC_ORIGINAL_NAME ${PACKAGE_NAME}.dll)