symbols-check: Add __cxa_guard_* to the list of approved symbols.

These are introduced by the compiler during static local initialization in
c++ for thread safety.  This seems to end up being public in the driver
with --static-libc++ on android.

Reviewed-by: <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6700>

bin/symbols-check.py

@@ -10,6 +10,9 @@ PLATFORM_SYMBOLS = [
     '__bss_end__',
     '__bss_start__',
     '__bss_start',
+    '__cxa_guard_abort',
+    '__cxa_guard_acquire',
+    '__cxa_guard_release',
     '__end__',
     '_bss_end__',
     '_edata',
@@ -18,7 +21,6 @@ PLATFORM_SYMBOLS = [
     '_init',
 ]
 
-
 def get_symbols_nm(nm, lib):
     '''
     List all the (non platform-specific) symbols exported by the library