diff --git a/CMakeLists.txt b/CMakeLists.txt
index 261fc93ea..9070c022a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,14 +41,6 @@ set_property(CACHE VTR_ASSERT_LEVEL PROPERTY STRINGS 0 1 2 3 4)
 #Create the project 
 project("OpenFPGA-tool-suites" C CXX)
 
-# Options
-# Option to enable/disable graphic in compilation
-option(ENABLE_VPR_GRAPHICS "Enables VPR graphics" ON)
-
-#Allow the user to decide weather to compile the graphics library
-set(VPR_USE_EZGL "auto" CACHE STRING "Specify whether vpr uses the graphics library")
-set_property(CACHE VPR_USE_EZGL PROPERTY STRINGS auto off on)
-
 # Version number
 file (STRINGS "VERSION.md" VERSION_NUMBER)
 string (REPLACE "." ";" VERSION_LIST ${VERSION_NUMBER})
@@ -172,27 +164,6 @@ message(STATUS "CMAKE_CXX_FLAGS: ${CMAKE_CXX_FLAGS}")
 #
 enable_testing()
 
-# set VPR_USE_EZGL in the root of VTR to decide whether to add
-# subdirectory of graphics library, which prevents users
-# without gtk/x11 libraries installed to build. VPR_USE_EZGL is
-# being used in both the vpr CMakeLists and libs/EXTERNAL CMakeLists.
-#
-# check if GTK and X11 are installed and turn on/off graphics
-if (VPR_USE_EZGL STREQUAL "auto")
-    find_package(PkgConfig REQUIRED)
-    pkg_check_modules(GTK3 QUIET gtk+-3.0)
-    pkg_check_modules(X11 QUIET x11)
-
-    if(GTK3_FOUND AND X11_FOUND)
-        set(VPR_USE_EZGL "on")
-        message(STATUS "VPR Graphics: Enabled")
-    else()
-        set(VPR_USE_EZGL "off")
-        message(STATUS "VPR Graphics: Disabled (required libraries missing, on debia/ubuntu try: sudo apt install libgtk-3 libx11-dev")
-    endif()
-endif()
-
-
 # 
 # Sub-projects
 #
diff --git a/libs/libbusgroup/src/bus_group_xml_constants.h b/libs/libbusgroup/src/bus_group_xml_constants.h
index 62b552f06..4b4d4c9c6 100644
--- a/libs/libbusgroup/src/bus_group_xml_constants.h
+++ b/libs/libbusgroup/src/bus_group_xml_constants.h
@@ -3,12 +3,12 @@
 
 /* Constants required by XML parser */
 
-constexpr char* XML_BUS_GROUP_NODE_NAME = "bus_group";
-constexpr char* XML_BUS_NODE_NAME = "bus";
-constexpr char* XML_BUS_PORT_ATTRIBUTE_NAME = "name";
-constexpr char* XML_BUS_BIG_ENDIAN_ATTRIBUTE_NAME = "big_endian";
-constexpr char* XML_PIN_NODE_NAME = "pin";
-constexpr char* XML_PIN_INDEX_ATTRIBUTE_NAME = "id";
-constexpr char* XML_PIN_NAME_ATTRIBUTE_NAME = "name";
+constexpr const char* XML_BUS_GROUP_NODE_NAME = "bus_group";
+constexpr const char* XML_BUS_NODE_NAME = "bus";
+constexpr const char* XML_BUS_PORT_ATTRIBUTE_NAME = "name";
+constexpr const char* XML_BUS_BIG_ENDIAN_ATTRIBUTE_NAME = "big_endian";
+constexpr const char* XML_PIN_NODE_NAME = "pin";
+constexpr const char* XML_PIN_INDEX_ATTRIBUTE_NAME = "id";
+constexpr const char* XML_PIN_NAME_ATTRIBUTE_NAME = "name";
 
 #endif