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

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

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