README: bump supported minimum glibc version to 2.31

The current glibc versions used by major distributions:
CentOS 9:  2.34
CentOS 10: 2.39
Fedora 40: 2.39
Fedora 41: 2.40
Fedora 42: 2.41
Ubuntu 20.04 LTS (focal): 2.31
Ubuntu 22.04 LTS (jammy): 2.35
Ubuntu 24.04 LTS (noble): 2.39
Ubuntu 24.10 (oracular):  2.40
Debian 11 (Bullseye, oldstable): 2.31
Debian 12 (Bookworm, stable):    2.36
openSUSE SLE-15-SP6: 2.38
openSUSE Tumbleweed: 2.40

Hence, based on our supporting policy, we can bump the base line to 2.31.
This commit does not change anything on our source code. But, will drop
many workarounds for supporting older glibc in later commits.

diff --git a/README b/README
index 5194faae5e818a490542cbd4706c8470f6ff130a..9b019396c8e472a42eabebf2634e5c3575aa852d 100644 (file)
--- a/README
+++ b/README
@@ -206,7 +206,7 @@ REQUIREMENTS:
         with audit being enabled. This works correctly only on kernels 3.14 and
         newer though. TL;DR: turn audit off, still.
 
-        glibc >= 2.16
+        glibc >= 2.31
         libcap
         libmount >= 2.30 (from util-linux)
                 (util-linux *must* be built without --enable-libmount-support-mtab)