--- CMakeLists.txt.orig	2018-01-04 18:38:27.000000000 -0700
+++ CMakeLists.txt	2018-08-19 17:57:01.000000000 -0700
@@ -36,7 +36,7 @@
 option(OCIO_PYGLUE_SONAME "If ON, soname/soversion will be set for Python module library" OFF)
 option(OCIO_PYGLUE_LIB_PREFIX "If ON, prefix the Python module with 'lib'" OFF)
 
-if(UNIX AND NOT APPLE)
+if(UNIX)
     option(USE_EXTERNAL_YAML "Use system installed yaml-cpp library." OFF)
     option(USE_EXTERNAL_TINYXML "Use system installed tinyxml library." OFF)
     option(USE_EXTERNAL_LCMS "Use system install lcms2 library." OFF)
@@ -385,7 +385,7 @@
     set(OCIO_INLINES_HIDDEN OFF)
 endif()
 
-set(EXTERNAL_COMPILE_FLAGS "-DTIXML_USE_STL ${YAML_CPP_COMPILE_FLAGS} ${GCC_COMPILE_FLAGS}")
+set(EXTERNAL_COMPILE_FLAGS "${YAML_CPP_COMPILE_FLAGS} ${GCC_COMPILE_FLAGS}")
 
 set(EXTERNAL_LINK_FLAGS "")
 set(EXTERNAL_LIBRARY_DIRS ${PROJECT_BINARY_DIR}/ext/dist/lib)