Revert "TMP: workaround to fix boost deprecation warning"

This reverts commit d0aada8.

Author: lkrcal

CMakeLists.txt

@@ -39,7 +39,7 @@ set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -ffast-math -DNDEBUG -fno-omit-frame-poi
 set(CMAKE_CXX_FLAGS_RELEASE "-O3 -ffast-math -DNDEBUG")
 
 if(NOT APPLE)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic -Werror -Wno-deprecated-declarations")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic -Werror")
 endif()