diff --git a/CMakeTestFiles/TestICGLinkedLibs.cpp b/CMakeTestFiles/TestICGLinkedLibs.cpp
new file mode 100644
index 00000000..bb243bcf
--- /dev/null
+++ b/CMakeTestFiles/TestICGLinkedLibs.cpp
@@ -0,0 +1,17 @@
+#include "llvm/Support/Host.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include "clang/Basic/Builtins.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Basic/TargetOptions.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/PreprocessorOptions.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Parse/ParseAST.h"
+
+int main() {
+	return 0;
+}
\ No newline at end of file
diff --git a/libexec/trick/sie_concat b/libexec/trick/sie_concat
index 676fac26..aa080e28 100755
--- a/libexec/trick/sie_concat
+++ b/libexec/trick/sie_concat
@@ -14,7 +14,9 @@ while(my $line = <$classes_resource>) {
 close($classes_resource);
 
 open(my $sim_services_resource, "<", "$ENV{TRICK_HOME}/trick_source/sim_services/include/sim_services_classes.resource")
-	or die "cannot open trick/trick_source/sim_services/include/sim_services_classes.resource";
+	or open(my $sim_services_resource, "<", "$ENV{TRICK_HOME}/temp_src/io_src/sim_services_classes.resource")
+	or die "cannot open sim_services_classes.resource";
+
 while(my $line = <$sim_services_resource>) {
 	print $S_sie_resource $line;
 }
diff --git a/trick_source/codegen/Interface_Code_Gen/CMakeLists.txt b/trick_source/codegen/Interface_Code_Gen/CMakeLists.txt
index 9a2b5684..ba656b12 100644
--- a/trick_source/codegen/Interface_Code_Gen/CMakeLists.txt
+++ b/trick_source/codegen/Interface_Code_Gen/CMakeLists.txt
@@ -23,6 +23,26 @@ set ( ICG_SRC
   ../../sim_services/UdUnits/map_trick_units_to_udunits
 )
 
+set (ICG_CLANGLIBS 
+    -lclangFrontend
+    -lclangDriver
+    -lclangSerialization
+    -lclangParse
+    -lclangSema
+    -lclangAnalysis
+    -lclangEdit
+    -lclangAST
+    -lclangLex
+    -lclangBasic
+  )
+
+try_compile(haveOldLibs "${CMAKE_BINARY_DIR}" "${PROJECT_SOURCE_DIR}/CMakeTestFiles/TestICGLinkedLibs.cpp" CMAKE_FLAGS "-DINCLUDE_DIRECTORIES=${LLVM_INCLUDE_DIRS}")
+if(NOT haveOldLibs)
+  set (ICG_CLANGLIBS 
+    -lclang-cpp
+  )
+endif()
+
 add_executable( trick-ICG ${ICG_SRC} )
 target_compile_options( trick-ICG PUBLIC -g -DTRICK_VERSION="${TRICK_MAJOR}.${TRICK_MINOR}.${TRICK_TINY}" -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS)
 target_compile_options( trick-ICG PUBLIC -DEXTERNAL_BUILD)
@@ -34,16 +54,7 @@ set_property(SOURCE trick-ICG APPEND PROPERTY OBJECT_DEPENDS ${CMAKE_BINARY_DIR}
 set_target_properties( trick-ICG PROPERTIES CXX_STANDARD 14)
 
 target_link_libraries( trick-ICG
-    -lclangFrontend
-    -lclangDriver
-    -lclangSerialization
-    -lclangParse
-    -lclangSema
-    -lclangAnalysis
-    -lclangEdit
-    -lclangAST
-    -lclangLex
-    -lclangBasic
+    ${ICG_CLANGLIBS}
     ${LLVM_LDFLAGS}
     ${LLVM_LIBRARIES}
     ${UDUNITS2_LIBRARIES}
diff --git a/trick_source/codegen/Interface_Code_Gen/PrintAttributes.cpp b/trick_source/codegen/Interface_Code_Gen/PrintAttributes.cpp
index 7671ef90..f91ea391 100644
--- a/trick_source/codegen/Interface_Code_Gen/PrintAttributes.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/PrintAttributes.cpp
@@ -276,7 +276,11 @@ void PrintAttributes::printEnum(EnumValues* ev) {
 void PrintAttributes::printSieClass( ClassValues * cv ) {
     std::string xmlFileName;
     if(sim_services_flag) {
+    #ifdef EXTERNAL_BUILD
+        xmlFileName = output_dir + "/sim_services_classes.resource";
+    #else
         xmlFileName = std::string(getenv("TRICK_HOME")) + "/trick_source/sim_services/include/sim_services_classes.resource";
+    #endif
     } else {
         xmlFileName = "build/classes.resource";
     }
@@ -313,7 +317,12 @@ void PrintAttributes::printSieClass( ClassValues * cv ) {
 void PrintAttributes::printSieEnum( EnumValues * ev ) {
     std::string xmlFileName;
     if(sim_services_flag) {
+    #ifdef EXTERNAL_BUILD
+        xmlFileName = output_dir + "/sim_services_classes.resource";
+    #else
         xmlFileName = std::string(getenv("TRICK_HOME")) + "/trick_source/sim_services/include/sim_services_classes.resource";
+    #endif
+
     } else {
         xmlFileName = "build/classes.resource";
     }