Installing PVR_=X11 or =Wayland

cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchains/Linux-gcc-armv7hf.cmake -DPVR_WINDOW_SYSTEM=X11 .
* download_external_project: Processing external project [glm]
* download_external_project: glm-0.9.9.4.tar.gz was found and hash matches, using local file.
* external_project: [glm] - Executing Generation.
* external_project: [glm] - Executing Build.
-- GLM: Build with fast math optimizations
GLM: GCC - GNU compiler
* download_external_project: Processing external project [pugixml]
* download_external_project: pugixml-1.10.tar.gz was found and hash matches, using local file.
* external_project: [pugixml] - Executing Generation.
* external_project: [pugixml] - Executing Build.
* download_external_project: Processing external project [glslang]
* download_external_project: glslang-11.2.0.tar.gz was found and hash matches, using local file.
* external_project: [glslang] - Executing Generation.
* external_project: [glslang] - Executing Build.
* download_external_project: Processing external project [VulkanMemoryAllocator]
* download_external_project: VulkanMemoryAllocator-v2.3.0.tar.gz was found and hash matches, using local file.
* external_project: [VulkanMemoryAllocator] - Executing Generation.
* external_project: [VulkanMemoryAllocator] - Executing Build.
CMake Error at /usr/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:165 (message):
  Could NOT find X11 (missing: X11_X11_LIB)
Call Stack (most recent call first):
  /usr/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:458 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-3.18/Modules/FindX11.cmake:414 (find_package_handle_standard_args)
  framework/PVRShell/CMakeLists.txt:92 (find_package)


-- Configuring incomplete, errors occurred!
See also "/home/phlastch/Native_SDK/buildBBB/CMakeFiles/CMakeOutput.log".
See also "/home/phlastch/Native_SDK/buildBBB/CMakeFiles/CMakeError.log".