package/mesa3d: add compile patch for linux < 3.5

The kcmp() system call first appeared in linux 3.5,
and was also not there before linux 5.12 if
CONFIG_CHECKPOINT_RESTORE was not set.

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

Signed-off-by: Thomas Devoogdt <thomas@devoogdt.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 7b71ce5018)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/mesa3d/0005-util-os_same_file_description-fix-unknown-linux-3.5-.patch

@@ -0,0 +1,68 @@
+From b60974fac8a2f4c85cbb2ca788fc4ec3e81998f9 Mon Sep 17 00:00:00 2001
+From: Thomas Devoogdt <thomas.devoogdt@barco.com>
+Date: Tue, 17 Aug 2021 11:54:49 +0200
+Subject: [PATCH] util: os_same_file_description: fix unknown linux < 3.5
+ syscall SYS_kcmp
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+https://man7.org/linux/man-pages/man2/kcmp.2.html
+
+The kcmp() system call first appeared in Linux 3.5.
+
+But was probably also not supported by all major platforms
+at that time. So fallback to the check that is done for windows.
+
+Signed-off-by: Thomas Devoogdt <thomas.devoogdt@barco.com>
+Acked-by: Yonggang Luo <luoyonggang@gmail.com>
+Acked-by: Michel Dänzer <mdaenzer@redhat.com>
+Upstream: https://gitlab.freedesktop.org/mesa/mesa/-/commit/3ef514982441ce496aa127611edd26b9867f4b95
+Signed-off-by: Thomas Devoogdt <thomas@devoogdt.com>
+---
+ src/util/os_file.c | 18 ++++++------------
+ 1 file changed, 6 insertions(+), 12 deletions(-)
+
+diff --git a/src/util/os_file.c b/src/util/os_file.c
+index 5fb30f2d908..464425a9b87 100644
+--- a/src/util/os_file.c
++++ b/src/util/os_file.c
+@@ -202,29 +202,23 @@ os_read_file(const char *filename, size_t *size)
+ /* copied from <linux/kcmp.h> */
+ #define KCMP_FILE 0
+ 
++#endif
++
+ int
+ os_same_file_description(int fd1, int fd2)
+ {
++#ifdef SYS_kcmp
+    pid_t pid = getpid();
++#endif
+ 
+    /* Same file descriptor trivially implies same file description */
+    if (fd1 == fd2)
+       return 0;
+ 
++#ifdef SYS_kcmp
+    return syscall(SYS_kcmp, pid, pid, KCMP_FILE, fd1, fd2);
+-}
+-
+ #else
+-
+-int
+-os_same_file_description(int fd1, int fd2)
+-{
+-   /* Same file descriptor trivially implies same file description */
+-   if (fd1 == fd2)
+-      return 0;
+-
+    /* Otherwise we can't tell */
+    return -1;
+-}
+-
+ #endif
++}
+-- 
+2.34.1
+