diff -Naur external_ispc/CMakeLists.txt external_ispc_fixed/CMakeLists.txt
--- external_ispc/CMakeLists.txt	2020-04-23 17:29:06 -0600
+++ external_ispc_fixed/CMakeLists.txt	2020-05-05 09:01:09 -0600
@@ -389,7 +389,7 @@
 
 # Link against Clang libraries
 foreach(clangLib ${CLANG_LIBRARY_LIST})
-    find_library(${clangLib}Path NAMES ${clangLib} HINTS ${LLVM_LIBRARY_DIRS})
+    find_library(${clangLib}Path NAMES ${clangLib} HINTS ${LLVM_LIBRARY_DIRS} ${CLANG_LIBRARY_DIR})
     list(APPEND CLANG_LIBRARY_FULL_PATH_LIST ${${clangLib}Path})
 endforeach()
 target_link_libraries(${PROJECT_NAME} ${CLANG_LIBRARY_FULL_PATH_LIST})
diff -Naur orig/CMakeLists.txt external_ispc/CMakeLists.txt
--- orig/CMakeLists.txt 2020-05-05 09:19:11 -0600
+++ external_ispc/CMakeLists.txt        2020-05-05 09:26:44 -0600
@@ -333,7 +333,7 @@

 # Include directories
 target_include_directories(${PROJECT_NAME} PRIVATE
-                           ${LLVM_INCLUDE_DIRS}
+                           ${LLVM_INCLUDE_DIRS} ${CLANG_INCLUDE_DIRS}
                            ${CMAKE_CURRENT_SOURCE_DIR}/src
                            ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR})
 # Compile options
diff -Naur orig/cmake/GenerateBuiltins.cmake.txt external_ispc/cmake/GenerateBuiltins.cmake.txt
+++ orig/cmake/GenerateBuiltins.cmake	2020-05-25 13:32:40.830803821 +0200
+++ external_ispc/cmake/GenerateBuiltins.cmake	2020-05-25 13:32:40.830803821 +0200
@@ -97,6 +97,8 @@
 
     if ("${bit}" STREQUAL "32" AND ${arch} STREQUAL "x86")
         set(target_arch "i386")
+        # Blender: disable 32bit due to build issues on Linux and being unnecessary.
+        set(SKIP ON)
     elseif ("${bit}" STREQUAL "64" AND ${arch} STREQUAL "x86")
         set(target_arch "x86_64")
     elseif ("${bit}" STREQUAL "32" AND ${arch} STREQUAL "arm")