diff -Naur OpenShadingLanguage-Release-1.9.9/src/include/OSL/llvm_util.h external_osl/src/include/OSL/llvm_util.h
--- OpenShadingLanguage-Release-1.9.9/src/include/OSL/llvm_util.h	2018-05-01 16:39:02 -0600
+++ external_osl/src/include/OSL/llvm_util.h	2018-08-25 14:05:00 -0600
@@ -33,6 +33,8 @@
 
 #include <vector>
 
+#define OSL_HAS_BLENDER_CLEANUP_FIX
+
 #ifdef LLVM_NAMESPACE
 namespace llvm = LLVM_NAMESPACE;
 #endif
@@ -487,6 +489,7 @@
     std::string func_name (llvm::Function *f);
 
     static size_t total_jit_memory_held ();
+    static void Cleanup ();
 
 private:
     class MemoryManager;
diff -Naur OpenShadingLanguage-Release-1.9.9/src/liboslexec/llvm_util.cpp external_osl/src/liboslexec/llvm_util.cpp
--- OpenShadingLanguage-Release-1.9.9/src/liboslexec/llvm_util.cpp	2018-05-01 16:39:02 -0600
+++ external_osl/src/liboslexec/llvm_util.cpp	2018-08-25 14:04:27 -0600
@@ -140,7 +140,10 @@
 };
 
 
-
+void LLVM_Util::Cleanup ()
+{
+       if(jitmm_hold) jitmm_hold->clear();
+}
 
 size_t
 LLVM_Util::total_jit_memory_held ()
diff -Naur org/CMakeLists.txt external_osl/CMakeLists.txt
--- org/CMakeLists.txt  2020-12-01 12:37:15 -0700
+++ external_osl/CMakeLists.txt 2021-01-20 13:26:50 -0700
@@ -84,6 +84,11 @@
      CACHE STRING "Directory where OptiX PTX files will be installed")
 set (CMAKE_DEBUG_POSTFIX "" CACHE STRING "Library naming postfix for Debug builds (e.g., '_debug')")

+set (USE_OIIO_STATIC ON CACHE BOOL "If OIIO is built static")
+if (USE_OIIO_STATIC)
+    add_definitions ("-DOIIO_STATIC_BUILD=1")
+    add_definitions ("-DOIIO_STATIC_DEFINE=1")
+endif ()

 set (OSL_NO_DEFAULT_TEXTURESYSTEM OFF CACHE BOOL "Do not use create a raw OIIO::TextureSystem")
 if (OSL_NO_DEFAULT_TEXTURESYSTEM)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 990f50d69..46ef7351d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -252,11 +252,9 @@ install (EXPORT OSL_EXPORTED_TARGETS
         FILE ${OSL_TARGETS_EXPORT_NAME}
         NAMESPACE ${PROJECT_NAME}::)
 
-
-
-
-osl_add_all_tests()
-
+if (${PROJECT_NAME}_BUILD_TESTS AND NOT ${PROJECT_NAME}_IS_SUBPROJECT)
+	osl_add_all_tests()
+endif ()
 
 if (NOT ${PROJECT_NAME}_IS_SUBPROJECT)
     include (packaging)
diff -Naur external_osl_orig/src/cmake/externalpackages.cmake external_osl/src/cmake/externalpackages.cmake
--- external_osl_orig/src/cmake/externalpackages.cmake  2021-06-01 13:44:18 -0600
+++ external_osl/src/cmake/externalpackages.cmake       2021-06-28 07:44:32 -0600
@@ -80,6 +80,7 @@


 checked_find_package (ZLIB REQUIRED)  # Needed by several packages
+checked_find_package (PNG REQUIRED)  # Needed since OIIO needs it

 # IlmBase & OpenEXR
 checked_find_package (OpenEXR REQUIRED
diff -Naur external_osl_orig/src/liboslcomp/oslcomp.cpp external_osl/src/liboslcomp/oslcomp.cpp
--- external_osl_orig/src/liboslcomp/oslcomp.cpp        2021-06-01 13:44:18 -0600
+++ external_osl/src/liboslcomp/oslcomp.cpp     2021-06-28 09:11:06 -0600
@@ -21,6 +21,13 @@
 #if !defined(__STDC_CONSTANT_MACROS)
 #    define __STDC_CONSTANT_MACROS 1
 #endif
+
+// clang uses CALLBACK in its templates which causes issues if it is already defined
+#ifdef _WIN32 && defined(CALLBACK)
+#    undef CALLBACK
+#endif
+
+//
 #include <clang/Basic/TargetInfo.h>
 #include <clang/Frontend/CompilerInstance.h>
 #include <clang/Frontend/TextDiagnosticPrinter.h>