ros2 foxy compile failure: unable to locate clang's built-in include directory

[flynneva]

System Info:

• Dell XPS 13 Laptop
• Ubuntu 20.04
• ROS2 Foxy: compiling from source with colcon build --symlink-install

Following the ros2 foxy compile from source instructions I receive some build errors.
Any ideas on what this might be caused from? I'll keep poking around to try and fix this on my own. Most likely it is my environment.

colcon build output

--- stderr: qt_gui_cpp                                                             
qt.shiboken: (typesystem) Unable to locate Clang's built-in include directory (neither by checking the environment variables LLVM_INSTALL_DIR, CLANG_INSTALL_DIR  nor running llvm-config). This may lead to parse errors.
(typesystem) clang_parseTranslationUnit2(0x0, cmd[26]=-fPIC -Wno-constant-logical-operand -std=c++14 -I/home/flynn/dev/ros/foxy/src/ros-visualization/qt_gui_core/qt_gui_cpp/include -I/home/flynn/dev/ros/foxy/src/ros-visualization/qt_gui_core/qt_gui_cpp/include -I/usr/include -I/home/flynn/dev/ros/foxy/install/ament_index_cpp/include -I/home/flynn/dev/ros/foxy/install/class_loader/include -I/usr/include -I/home/flynn/dev/ros/foxy/install/rcutils/include -I/home/flynn/dev/ros/foxy/install/rcpputils/include -I/home/flynn/dev/ros/foxy/install/pluginlib/include -I/usr/include/x86_64-linux-gnu/qt5 -I/usr/include/x86_64-linux-gnu/qt5/QtWidgets -I/usr/include/x86_64-linux-gnu/qt5/QtGui -I/usr/include/x86_64-linux-gnu/qt5/QtCore -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++ -I/usr/include/PySide2 -I/usr/include/c++/9 -I/usr/include/x86_64-linux-gnu/c++/9 -I/usr/include/c++/9/backward -I/usr/lib/gcc/x86_64-linux-gnu/9/include -I/usr/local/include -I/usr/include/x86_64-linux-gnu -I/usr/include /tmp/global_RMMohD.hpp)
qt.shiboken: (typesystem) Enum 'RCUTILS_LOG_SEVERITY' does not have a type entry
qt.shiboken: (typesystem) While traversing QOpenGLShaderProgram: setAttributeArray(int,const float*,int,int): Cannot use parameter 2 as an array: <array> modification already applied.
qt.shiboken: (typesystem) class 'QAccessibleWidget' inherits from unknown base class 'QAccessibleActionInterface'
qt.shiboken: (typesystem) class not found for setup inheritance 'QAccessibleActionInterface'
make[3]: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.
/usr/bin/ld: /usr/local/lib/libpython3.8.a(object.o): relocation R_X86_64_PC32 against symbol `stderr@@GLIBC_2.2.5' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status
make[3]: *** [Makefile:38: "/home/flynn/dev/ros/foxy/build/qt_gui_cpp/src/qt_gui_cpp_sip/libqt_gui_cpp_sip".so] Error 1
make[2]: *** [src/qt_gui_cpp_sip/CMakeFiles/libqt_gui_cpp_sip.dir/build.make:61: src/qt_gui_cpp_sip/libqt_gui_cpp_sip.so] Error 2
make[1]: *** [CMakeFiles/Makefile2:264: src/qt_gui_cpp_sip/CMakeFiles/libqt_gui_cpp_sip.dir/all] Error 2
make: *** [Makefile:141: all] Error 2
---
Failed   <<< qt_gui_cpp	[ Exited with code 2 ]

[flynneva]

duplicate issue as #212