[Hexagon] Disable thread_local on Hexagon (#9025)

This is specific to running code on hardware: libc++abi can create
TLS keys with destructors in the libc++abi library. Despite that,
the library gets unloaded before the keys are destroyed, leading
to a crash. Turning off the use of `thread_local` is a workaround
for this.

Author: Krzysztof Parzyszek

CMakeLists.txt

@@ -310,6 +310,7 @@ if(BUILD_FOR_HEXAGON)
   endif()
 
   add_definitions(-D_MACH_I32=int)
+  add_definitions(-DDMLC_CXX11_THREAD_LOCAL=0)
 endif()
 
 # Package runtime rules