threads.h: avoid defining gettid on glibc >= 2.30

The issue in https://bugs.chromium.org/p/chromium/issues/detail?id=1182060 also
exists on glibc 2.30 and 2.31 since `gettid` was Introduced in glibc 2.30.

See https://man7.org/linux/man-pages/man2/gettid.2.html

Bug: 285204695
Test: Build
Change-Id: I7e534edf8c0a20c415232bcfffabbf2c1d6eec98
diff --git a/libcutils/threads.cpp b/libcutils/threads.cpp
index 6ece7a3..2638720 100644
--- a/libcutils/threads.cpp
+++ b/libcutils/threads.cpp
@@ -25,9 +25,9 @@
 #include <windows.h>
 #endif
 
-#if defined(__BIONIC__) || defined(__GLIBC__) && __GLIBC_MINOR__ >= 32
+#if defined(__BIONIC__) || defined(__GLIBC__) && __GLIBC_MINOR__ >= 30
 // No definition needed for Android because we'll just pick up bionic's copy.
-// No definition needed for Glibc >= 2.32 because it exposes its own copy.
+// No definition needed for Glibc >= 2.30 because it exposes its own copy.
 #else
 pid_t gettid() {
 #if defined(__APPLE__)