Ignore pthread_getconcurrency/pthread_setconcurrency.

They're marked obsolescent in POSIX, don't clearly mean anything, aren't
portable because the values don't mean anything, and are no-ops in other
C libraries that do "implement" them.

Bug: N/A
Test: N/A
Change-Id: I07342a0a6a5f6616a8432bfea24ed944c7971d27
diff --git a/libc/tools/check-symbols-glibc.py b/libc/tools/check-symbols-glibc.py
index 7ede2e6..7657925 100755
--- a/libc/tools/check-symbols-glibc.py
+++ b/libc/tools/check-symbols-glibc.py
@@ -209,6 +209,8 @@
   'mq_timedreceive', # disallowed by SELinux
   'mq_timedsend', # disallowed by SELinux
   'mq_unlink', # disallowed by SELinux
+  'pthread_getconcurrency', # marked obsolescent
+  'pthread_setconcurrency', # marked obsolescent
   'putmsg', # obsolete
   'putpmsg', # obsolete
   'pututxline', # no utmp on Android