This check is redundant. The appropriate versions of yaml-cpp
already had a dependency on Boost, but that's not even the case anymore.

Check has been dropped upstream since.
https://bugs.gentoo.org/747553
----
diff --git a/CMakeLists.txt b/CMakeLists.txt
index eb20913..434e38b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -272,24 +272,6 @@ if(USE_EXTERNAL_YAML)
     mark_as_advanced(YAML_CPP_INCLUDE_DIR YAML_CPP_LIBRARY YAML-CPP_FOUND)
 
     if(YAML_CPP_FOUND)
-        if(YAML_CPP_VERSION VERSION_GREATER "0.5.0")
-            # Need to also get the boost headers here, as yaml-cpp 0.5.0+ requires them.
-            # Don't bother doing this step if we are already including the boost headers for shared_ptr
-            if(NOT OCIO_USE_BOOST_PTR)
-                set(Boost_ADDITIONAL_VERSIONS "1.49" "1.45" "1.44" "1.43" "1.43.0" "1.42"
-                                              "1.42.0" "1.41" "1.41.0" "1.40"
-                                              "1.40.0" "1.39" "1.39.0" "1.38"
-                                              "1.38.0" "1.37" "1.37.0" "1.34.1"
-                                              "1_34_1")
-                set(Boost_USE_MULTITHREADED ON)
-                find_package(Boost 1.34)
-                if(NOT Boost_FOUND)
-                    message(FATAL_ERROR "Error: Detected system yaml-cpp version ${YAML_CPP_VERSION} is greater than 0.5.0, and therefore requires boost, but a boost installation could not be found.")
-                endif()
-
-                set(EXTERNAL_INCLUDE_DIRS ${EXTERNAL_INCLUDE_DIRS} ${Boost_INCLUDE_DIR})
-            endif()
-        endif()
         set(EXTERNAL_INCLUDE_DIRS ${EXTERNAL_INCLUDE_DIRS} ${YAML_CPP_INCLUDE_DIRS})
     else(YAML_CPP_FOUND)
         message(FATAL_ERROR "ERROR: System yaml-cpp library was not found. Make sure the library is installed and the pkg-config file exists.")