move joinPaths to utils.cpp

Change-Id: I8012fa004d174ddf42086b109caab3f2d7857d1e
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3ac9278..5fa1ac2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -51,6 +51,7 @@
     src/CTree.cpp
     src/CParser.cpp
     src/ast.cpp
+    src/utils.cpp
     )
 
 add_library(parser STATIC ${parser_SRCS})