From ed1f7fe812e20b54bc58222312d885291110b952 Mon Sep 17 00:00:00 2001
From: Kittywhiskers Van Gogh <63189531+kwvg@users.noreply.github.com>
Date: Sun, 3 Nov 2024 09:33:56 +0000
Subject: [PATCH] merge bitcoin#28069: Remove librt usage from release binaries

---
 configure.ac                                  |  2 -
 contrib/devtools/symbol-check.py              |  1 -
 contrib/guix/manifest.scm                     |  3 +-
 .../guix/patches/glibc-2.27-no-librt.patch    | 53 +++++++++++++++++++
 4 files changed, 55 insertions(+), 4 deletions(-)
 create mode 100644 contrib/guix/patches/glibc-2.27-no-librt.patch

diff --git a/configure.ac b/configure.ac
index 0acc144585..08006d3c98 100644
--- a/configure.ac
+++ b/configure.ac
@@ -959,8 +959,6 @@ if test x$ac_cv_sys_large_files != x &&
   CPPFLAGS="$CPPFLAGS -D_LARGE_FILES=$ac_cv_sys_large_files"
 fi
 
-AC_SEARCH_LIBS([clock_gettime],[rt])
-
 if test "x$enable_gprof" = xyes; then
     dnl -pg is incompatible with -pie. Since hardening and profiling together doesn't make sense,
     dnl we simply make them mutually exclusive here. Additionally, hardened toolchains may force
diff --git a/contrib/devtools/symbol-check.py b/contrib/devtools/symbol-check.py
index fd070b2823..7cc377b982 100755
--- a/contrib/devtools/symbol-check.py
+++ b/contrib/devtools/symbol-check.py
@@ -101,7 +101,6 @@ ELF_ALLOWED_LIBRARIES = {
 'libc.so.6', # C library
 'libpthread.so.0', # threading
 'libm.so.6', # math library
-'librt.so.1', # real-time (clock)
 'libatomic.so.1',
 'ld-linux-x86-64.so.2', # 64-bit dynamic linker
 'ld-linux.so.2', # 32-bit dynamic linker
diff --git a/contrib/guix/manifest.scm b/contrib/guix/manifest.scm
index 63b2a1aded..38d1c231dc 100644
--- a/contrib/guix/manifest.scm
+++ b/contrib/guix/manifest.scm
@@ -561,7 +561,8 @@ inspecting signatures in Mach-O binaries.")
                (base32
                 "0wm0if2n4z48kpn85va6yb4iac34crds2f55ddpz1hykx6jp1pb6"))
               (patches (search-our-patches "glibc-2.27-fcommon.patch"
-                                           "glibc-2.27-guix-prefix.patch"))))))
+                                           "glibc-2.27-guix-prefix.patch"
+                                           "glibc-2.27-no-librt.patch"))))))
 
 (packages->manifest
  (append
diff --git a/contrib/guix/patches/glibc-2.27-no-librt.patch b/contrib/guix/patches/glibc-2.27-no-librt.patch
new file mode 100644
index 0000000000..4f2092ba7e
--- /dev/null
+++ b/contrib/guix/patches/glibc-2.27-no-librt.patch
@@ -0,0 +1,53 @@
+This patch can be dropped when we are building with glibc 2.30+.
+
+commit 6e41ef56c9baab719a02f1377b1e7ce7bff61e73
+Author: Florian Weimer <fweimer@redhat.com>
+Date:   Fri Feb 8 10:21:56 2019 +0100
+
+    rt: Turn forwards from librt to libc into compat symbols [BZ #24194]
+    
+    As the  result of commit 6e6249d0b461b952d0f544792372663feb6d792a
+    ("BZ#14743: Move clock_* symbols from librt to libc."), in glibc 2.17,
+    clock_gettime, clock_getres, clock_settime, clock_getcpuclockid,
+    clock_nanosleep were added to libc, and the file rt/clock-compat.c
+    was added with forwarders to the actual implementations in libc.
+    These forwarders were wrapped in
+
+    #if SHLIB_COMPAT (librt, GLIBC_2_2, GLIBC_2_17)
+    
+    so that they are not present for newer architectures (such as
+    powerpc64le) with a 2.17 or later ABI baseline.  But the forwarders
+    were not marked as compatibility symbols.  As a result, on older
+    architectures, historic configure checks such as
+    
+    AC_CHECK_LIB(rt, clock_gettime)
+    
+    still cause linking against librt, even though this is completely
+    unnecessary.  It also creates a needless porting hazard because
+    architectures behave differently when it comes to symbol availability.
+    
+    Reviewed-by: Carlos O'Donell <carlos@redhat.com>
+
+diff --git a/rt/clock-compat.c b/rt/clock-compat.c
+index f816973c05..11e71aa890 100644
+--- a/rt/clock-compat.c
++++ b/rt/clock-compat.c
+@@ -30,14 +30,16 @@
+ #if HAVE_IFUNC
+ # undef INIT_ARCH
+ # define INIT_ARCH()
+-# define COMPAT_REDIRECT(name, proto, arglist) libc_ifunc (name, &__##name)
++# define COMPAT_REDIRECT(name, proto, arglist) libc_ifunc (name, &__##name) \
++    compat_symbol (librt, name, name, GLIBC_2_2);
+ #else
+ # define COMPAT_REDIRECT(name, proto, arglist)				      \
+   int									      \
+   name proto								      \
+   {									      \
+     return __##name arglist;						      \
+-  }
++  }									      \
++  compat_symbol (librt, name, name, GLIBC_2_2);
+ #endif
+ 
+ COMPAT_REDIRECT (clock_getres,