diff --git a/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp b/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp
index 5809dfe0..08ee6d91 100644
--- a/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp
@@ -430,7 +430,7 @@ std::ostream & operator << (std::ostream & os , FieldDescription & fdes ) {
     os << "    bitfield_word_offset = " << fdes.bitfield_word_offset << std::endl ;
     os << "    num_dims = " << fdes.num_dims << std::endl ;
     os << "    array_sizes =" ;
-    for( unsigned int ii ; ii < 8 ; ii++ ) {
+    for( unsigned int ii = 0 ; ii < 8 ; ii++ ) {
         os << " " << fdes.array_sizes[ii] ;
     }
     os << std::endl ;
diff --git a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp
index 72e01a75..3e842375 100644
--- a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp
@@ -32,22 +32,19 @@ void HeaderSearchDirs::AddCompilerBuiltInSearchDirs () {
     const bool IsFramework = false;
     const bool IsSysRootRelative = true;
 
-#ifdef __linux
     // Add clang specific include directory first.  Only required on linux systems. :(
+    // This is so that ICG will find clang friendly headers first.  gcc headers cause
+    // all kinds of problems.  On macs all headers are clang friendly.
+#if __linux
     std::stringstream icg_dir ;
-    icg_dir << std::string(getenv("TRICK_HOME")) << "/trick_source/codegen/Interface_Code_Gen/lib/clang/" ;
+    //icg_dir << std::string(getenv("TRICK_HOME")) << "/libexec/trick/lib/clang/" ;
+    icg_dir << LLVM_HOME << "/lib/clang/" ;
     icg_dir << __clang_major__ << "." << __clang_minor__ ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 4)
 #ifdef __clang_patchlevel__
     icg_dir << "." << __clang_patchlevel__  ;
-#endif
 #endif
     icg_dir << "/include" ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
     hso.AddPath(icg_dir.str() , clang::frontend::System, IsFramework, IsSysRootRelative);
-#else
-    hso.AddPath(icg_dir.str() , clang::frontend::System, IsUserSupplied, IsFramework, IsSysRootRelative);
-#endif
 #endif
 
     fp = popen("${TRICK_HOME}/bin/trick-gte TRICK_CPPC" , "r") ;
@@ -79,11 +76,7 @@ void HeaderSearchDirs::AddCompilerBuiltInSearchDirs () {
             //std::cout << "dir = " << dir << std::endl ;
             if ( resolved_path != NULL ) {
                 //std::cout << "gcc resolved_path = " << resolved_path << std::endl ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
                 hso.AddPath(resolved_path , clang::frontend::System, IsFramework, IsSysRootRelative);
-#else
-                hso.AddPath(resolved_path , clang::frontend::System, IsUserSupplied, IsFramework, IsSysRootRelative);
-#endif
                 free(resolved_path) ;
             }
         } else if ( !strncmp( line, "#include <...>", 14 )) {
@@ -103,11 +96,7 @@ void HeaderSearchDirs::AddUserSearchDirs ( std::vector<std::string> & include_di
         char * resolved_path = almostRealPath(include_dirs[ii].c_str()) ;
         if ( resolved_path != NULL ) {
             //std::cout << "adding resolved_path = " << resolved_path << std::endl ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
             hso.AddPath(resolved_path , clang::frontend::Angled, false, true);
-#else
-            hso.AddPath(resolved_path , clang::frontend::Angled, true, false, true);
-#endif
             // Add the path as a system path as well for those included files that are erroneously in <>
         }
     }
@@ -120,21 +109,13 @@ void HeaderSearchDirs::AddTrickSearchDirs () {
     if ( trick_home != NULL ) {
         std::string temp_dir = std::string(trick_home) + "/include/trick" ;
         char * resolved_path = almostRealPath(temp_dir.c_str() ) ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
         hso.AddPath(resolved_path , clang::frontend::Quoted, false, true);
-#else
-        hso.AddPath(resolved_path , clang::frontend::Quoted, true, false, true);
-#endif
         trick_include_dir = std::string(resolved_path) ;
         free(resolved_path) ;
 
         temp_dir = std::string(trick_home) + "/trick_source" ;
         resolved_path = almostRealPath(temp_dir.c_str() ) ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
         hso.AddPath(resolved_path , clang::frontend::Quoted, false, true);
-#else
-        hso.AddPath(resolved_path , clang::frontend::Quoted, true, false, true);
-#endif
         trick_source_dir = std::string(resolved_path) ;
         free(resolved_path) ;
     }
diff --git a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh
index fe6c60e1..eb45dd76 100644
--- a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh
+++ b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh
@@ -7,11 +7,7 @@
 #include <string>
 
 #include "clang/Lex/HeaderSearch.h"
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
 #include "clang/Lex/HeaderSearchOptions.h"
-#else
-#include "clang/Frontend/HeaderSearchOptions.h"
-#endif
 #include "clang/Lex/Preprocessor.h"
 
 /**
diff --git a/trick_source/codegen/Interface_Code_Gen/main.cpp b/trick_source/codegen/Interface_Code_Gen/main.cpp
index 5cfe2925..5e95a7eb 100644
--- a/trick_source/codegen/Interface_Code_Gen/main.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/main.cpp
@@ -62,7 +62,7 @@ Most of the main program is pieced together from examples on the web. We are doi
 */
 int main( int argc , char * argv[] ) {
 
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
+#if (__clang_major__ >= 6) || ((__clang_major__ == 3) && (__clang_minor__ >= 5))
     clang::TargetOptions to;
 #elif (__clang_major__ == 3) && (__clang_minor__ >= 3)
     clang::TargetOptions * to = new clang::TargetOptions() ;
@@ -85,11 +85,7 @@ int main( int argc , char * argv[] ) {
         return 0 ;
     }
 
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
     ci.createDiagnostics();
-#else
-    ci.createDiagnostics(0,NULL);
-#endif
     clang::DiagnosticOptions & diago = ci.getDiagnosticOpts() ;
     diago.ShowColors = 1 ;
     ci.getDiagnostics().setIgnoreAllWarnings(true) ;
@@ -102,14 +98,10 @@ int main( int argc , char * argv[] ) {
     ci.getLangOpts().CXXExceptions = true ;
 
     // Activate C++11 parsing
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
     ci.getLangOpts().CPlusPlus11 = true ;
-#else
-    ci.getLangOpts().CPlusPlus0x = true ;
-#endif
 
     // Set the default target architecture
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
+#if (__clang_major__ >= 6) || (__clang_major__ == 3) && (__clang_minor__ >= 5)
     to.Triple = llvm::sys::getDefaultTargetTriple();
 #elif (__clang_major__ == 3) && (__clang_minor__ >= 3)
     to->Triple = llvm::sys::getDefaultTargetTriple();
@@ -117,7 +109,7 @@ int main( int argc , char * argv[] ) {
     to.Triple = llvm::sys::getDefaultTargetTriple();
 #endif
 
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
+#if (__clang_major__ >= 6) || (__clang_major__ == 3) && (__clang_minor__ >= 5)
     std::shared_ptr<clang::TargetOptions> shared_to  = std::make_shared<clang::TargetOptions>(to) ;
     clang::TargetInfo *pti = clang::TargetInfo::CreateTargetInfo(ci.getDiagnostics(), shared_to);
 #else
@@ -128,7 +120,7 @@ int main( int argc , char * argv[] ) {
     // Create all of the necessary managers.
     ci.createFileManager();
     ci.createSourceManager(ci.getFileManager());
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
+#if (__clang_major__ >= 6) || (__clang_major__ == 3) && (__clang_minor__ >= 5)
     ci.createPreprocessor(clang::TU_Complete);
 #else
     ci.createPreprocessor();
@@ -151,12 +143,7 @@ int main( int argc , char * argv[] ) {
 
     // Add our comment saver as a comment handler in the preprocessor
     CommentSaver cs(ci.getSourceManager()) ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
     pp.addCommentHandler(&cs) ;
-#else
-    pp.AddCommentHandler(&cs) ;
-#endif
-
 
     PrintAttributes pa( attr_version, hsd, cs, ci, force, sim_services_flag) ;
 
@@ -165,7 +152,7 @@ int main( int argc , char * argv[] ) {
 
     // Tell the compiler to use our ICGASTconsumer
     ICGASTConsumer *astConsumer = new ICGASTConsumer(ci, hsd, cs, pa);
-#if (__clang_major__ == 3) && (__clang_minor__ >= 6)
+#if (__clang_major__ >= 6) || ((__clang_major__ == 3) && (__clang_minor__ >= 6))
     std::unique_ptr<clang::ASTConsumer> unique_ast(astConsumer) ;
     ci.setASTConsumer(std::move(unique_ast));
 #else
@@ -186,7 +173,7 @@ int main( int argc , char * argv[] ) {
 
     // Open up the input file and parse it.
     const clang::FileEntry *pFile = ci.getFileManager().getFile(input_file_full_path);
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
+#if (__clang_major__ >= 6) || ((__clang_major__ == 3) && (__clang_minor__ >= 5))
     ci.getSourceManager().setMainFileID(ci.getSourceManager().createFileID(pFile, clang::SourceLocation(), clang::SrcMgr::C_User));
 #else
     ci.getSourceManager().createMainFileID(pFile);
diff --git a/trick_source/codegen/Interface_Code_Gen/makefile b/trick_source/codegen/Interface_Code_Gen/makefile
index 115a31cb..147cefc9 100644
--- a/trick_source/codegen/Interface_Code_Gen/makefile
+++ b/trick_source/codegen/Interface_Code_Gen/makefile
@@ -2,20 +2,15 @@
 # The config_${HOST_TYPE}.mk file provides LLVM_HOME
 include ${TRICK_HOME}/share/trick/makefiles/Makefile.common
 
-RTTIFLAG := -fno-rtti
-LLVM_VERSION := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --version)
-ifneq ($(LLVM_HOME),)
 CC := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --bindir)/clang
 CXX := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --bindir)/clang++
-CXXFLAGS := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --cxxflags) -I$(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --includedir) $(RTTIFLAG) -g -O0
-LLVMLIBDIR := -L$(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --libdir)
-endif
-LLVMLDFLAGS := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --ldflags)
-OBJ_DIR :=  object_$(TRICK_HOST_CPU)
+CXXFLAGS := -I${LLVM_HOME}/include -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -fno-rtti
 
-CLANG_VERSION := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --version)
 CLANG_MINOR_GTEQ5 := $(shell expr `$(LLVM_HOME)/bin/$(LLVM_CONFIG) --version | cut -f2 -d. ` \>= 5 )
-CLANG_LIBDIR := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --libdir)
+
+LLVMLDFLAGS := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --ldflags)
+
+OBJ_DIR :=  object_$(TRICK_HOST_CPU)
 
 ifeq ($(IS_CC_CLANG), 0)
 CXXFLAGS += -DGCC_MAJOR=$(GCC_MAJOR) -DGCC_MINOR=$(GCC_MINOR)
@@ -31,53 +26,39 @@ UNITS_CONV_SRC = ${TRICK_HOME}/trick_source/trick_utils/units/src/units_conv.c
 UNITS_CONV_INCLUDE = -I${TRICK_HOME}/include
 UNITS_CONV_OBJ = $(OBJ_DIR)/units_conv.o
 
+CLANGLIBS = \
+    -lclangFrontend \
+    -lclangDriver \
+    -lclangSerialization \
+    -lclangParse \
+    -lclangSema \
+    -lclangAnalysis \
+    -lclangEdit \
+    -lclangAST \
+    -lclangLex \
+    -lclangBasic \
+
+ifeq ($(TRICK_HOST_TYPE),Linux)
+CLANGLIBS += $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --libs)
 ifeq ($(CLANG_MINOR_GTEQ5),1)
-LLVMLDFLAGS += $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --system-libs)
+CXXFLAGS += -std=c++11
+CLANGLIBS += $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --system-libs)
+endif
 endif
 
-ifeq ($(CLANG_VERSION),3.1)
-CLANGLIBS = \
-    -lclangFrontend \
-    -lclangDriver \
-    -lclangSerialization \
-    -lclangParse \
-    -lclangSema \
-    -lclangAnalysis \
-    -lclangRewrite \
-    -lclangEdit \
-    -lclangAST \
-    -lclangLex \
-    -lclangBasic \
-    -lLLVMMC \
-    -lLLVMSupport
-else
-CLANGLIBS = \
-    -lclangFrontend \
-    -lclangDriver \
-    -lclangSerialization \
-    -lclangParse \
-    -lclangSema \
-    -lclangAnalysis \
-    -lclangEdit \
-    -lclangAST \
-    -lclangLex \
-    -lclangBasic \
-    $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --libs)
+ifeq ($(TRICK_HOST_TYPE),Darwin)
+CXXFLAGS += -std=c++11
+CLANGLIBS += -lLLVMOption -lLLVMMCParser -lLLVMBitReader -lLLVMMC -lLLVMSupport $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --system-libs)
 endif
 
-all: $(ICG) lib/clang/$(LLVM_VERSION)
+all: $(ICG)
 
 $(ICG): $(OBJECTS) $(UNITS_CONV_OBJ)
-	$(CXX) -o $@ $(OBJECTS) $(UNITS_CONV_OBJ) $(LLVMLIBDIR) $(CLANGLIBS) $(LLVMLDFLAGS)
-
-lib/clang:
-	mkdir -p $@
-
-lib/clang/$(LLVM_VERSION): | lib/clang
-	cp -r $(CLANG_LIBDIR)/clang/$(LLVM_VERSION) lib/clang
+	$(CXX) -o $@ $(OBJECTS) $(UNITS_CONV_OBJ) $(LLVMLDFLAGS) $(CLANGLIBS)
 
 # Only FieldDescription.cpp includes the units conversion header.
 $(OBJ_DIR)/FieldDescription.o : CXXFLAGS += $(UNITS_CONV_INCLUDE)
+$(OBJ_DIR)/HeaderSearchDirs.o : CXXFLAGS += -DLLVM_HOME=\"${LLVM_HOME}\"
 $(OBJ_DIR)/main.o : CXXFLAGS += $(UNITS_CONV_INCLUDE)
 
 $(OBJECTS): $(OBJ_DIR)/%.o : %.cpp
@@ -91,8 +72,5 @@ $(OBJECTS) $(UNITS_CONV_OBJ) : | $(OBJ_DIR)
 $(OBJ_DIR):
 	mkdir -p $(OBJ_DIR)
 
-# if an LLVM_HOME is not specified, then ICG cannot be rebuilt... don't delete it
 clean:
-ifneq ($(LLVM_HOME),)
-	-rm -rf $(OBJ_DIR) $(ICG) lib
-endif
+	rm -rf $(OBJ_DIR) $(ICG)