From 198b3dd2d0b4d83c873b2ce480837edacc0f35ab Mon Sep 17 00:00:00 2001
From: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Date: Fri, 1 Mar 2024 16:25:11 -0500
Subject: [PATCH] disable _FILE_OFFSET_BITS in mmap_hook.cc

Debian is doing massive rebuild of everything with 64-bit off_t (and
time_t), but on those systems where it matters, glibc still has mmap
with 32-bit off_t argument and mmap64 with 64-bit off_t. Since we're
aiming to match glibc's ABI, we need to see system's native off_t
width.
---
 src/mmap_hook.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/mmap_hook.cc b/src/mmap_hook.cc
index 913fa03..b2651e3 100644
--- a/src/mmap_hook.cc
+++ b/src/mmap_hook.cc
@@ -29,6 +29,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+// We require "native" off_t for the system. So that we're able to
+// interpose native libc's mmap/mmap64 correctly. Thus we "turn off"
+// _FILE_OFFSET_BITS define even if user asked for 64-bit off_t.
+#undef _FILE_OFFSET_BITS
+
 #include <config.h>
 
 #include "mmap_hook.h"