SWDEV-273235 - [PAL] Ignore system headers on Linux

CMake always searches system paths for specified files before resorting
to the hints we give it. We should not be using elf and GL headers
from /usr/include.

Change-Id: I2172ce3da9cc101ced63e22d95ecc031b94f0a67


[ROCm/clr commit: a2612343d5]

projects/clr/rocclr/cmake/FindAMD_HSA_LOADER.cmake

@@ -28,7 +28,8 @@ find_path(AMD_LIBELF_INCLUDE_DIR libelf.h
   PATHS
     ${CMAKE_SOURCE_DIR}/hsail-compiler/lib/loaders/elf/utils/libelf
     ${CMAKE_SOURCE_DIR}/../hsail-compiler/lib/loaders/elf/utils/libelf
-    ${CMAKE_SOURCE_DIR}/../../hsail-compiler/lib/loaders/elf/utils/libelf)
+    ${CMAKE_SOURCE_DIR}/../../hsail-compiler/lib/loaders/elf/utils/libelf
+  NO_DEFAULT_PATH)
 
 find_path(AMD_HSAIL_INCLUDE_DIR hsa.h
   HINTS

projects/clr/rocclr/cmake/FindAMD_UGL.cmake

@@ -35,7 +35,8 @@ find_path(AMD_UGL_INCLUDE_DIR GL/glx.h
     ${CMAKE_SOURCE_DIR}/../drivers/drivers
     ${CMAKE_SOURCE_DIR}/../../drivers/drivers
   PATH_SUFFIXES
-    ugl/inc)
+    ugl/inc
+  NO_DEFAULT_PATH)
 
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(AMD_UGL