Build: Include preflight and postflight scripts for mac

Commit 441f16bd55d2a26e4dd59df6129c6092f099cbca introduced a bug where
the preflight and postflight scripts for mac were not getting included
in the .dmg file. This commit adds an if check for the APPLE platform to
include these scripts necessary for dmg installation.

Closes #331
diff --git a/deploy/CMakeLists.txt b/deploy/CMakeLists.txt
index d25839a..e727e92 100644
--- a/deploy/CMakeLists.txt
+++ b/deploy/CMakeLists.txt
@@ -86,12 +86,14 @@
 
 
 # -- Finally do the packaging! -------------------------------------------------
-if(IS_REDHAT)
-  set(CPACK_RPM_POST_INSTALL_SCRIPT_FILE "${CMAKE_CURRENT_SOURCE_DIR}/rpm_post.sh")
-  set(CPACK_RPM_POST_UNINSTALL_SCRIPT_FILE "${CMAKE_CURRENT_SOURCE_DIR}/rpm_post_uninstall.sh")
+if(APPLE)
   set(CPACK_PREFLIGHT_SCRIPT ${CMAKE_CURRENT_SOURCE_DIR}/preflight.sh)
   set(CPACK_POSTFLIGHT_SCRIPT ${CMAKE_CURRENT_SOURCE_DIR}/postflight.sh)
   set(CPACK_MONOLITHIC_INSTALL 1)
+elseif(IS_REDHAT)
+  set(CPACK_RPM_POST_INSTALL_SCRIPT_FILE "${CMAKE_CURRENT_SOURCE_DIR}/rpm_post.sh")
+  set(CPACK_RPM_POST_UNINSTALL_SCRIPT_FILE "${CMAKE_CURRENT_SOURCE_DIR}/rpm_post_uninstall.sh")
+  set(CPACK_MONOLITHIC_INSTALL 1)
 elseif(IS_DEBIAN)
   if(NOT CREATE_RPM_FOR_UBUNTU)
     set(CPACK_PACKAGE_FILE_NAME