Add custom LLVM compiler path support (#102)

install.sh

@@ -216,7 +216,9 @@ fi
 if [ "$1" = "install" ]; then
 
   # Use custom compiler paths if defined
-  if [ -n "${CUSTOM_GCC_PATH}" ]; then
+  if [ "$_compiler_name" = "-llvm" ] && [ -n "${CUSTOM_LLVM_PATH}" ]; then
+    PATH=${CUSTOM_LLVM_PATH}/bin:${CUSTOM_LLVM_PATH}/lib:${CUSTOM_LLVM_PATH}/include:${PATH}
+  elif [ -n "${CUSTOM_GCC_PATH}" ]; then
     PATH=${CUSTOM_GCC_PATH}/bin:${CUSTOM_GCC_PATH}/lib:${CUSTOM_GCC_PATH}/include:${PATH}
   fi