qemu: fix build issue on new hosts with glibc 2.30

This fixes the following error:

TOPDIR/tmp/work/x86_64-linux/qemu-native/3.1.0-r0/qemu-3.1.0/linux-user/syscall.c:254:16: error: static declaration of ‘gettid’ follows non-static declaration
 254 | _syscall0(int, gettid)
 |                ^~~~~~
 TOPDIR/tmp/work/x86_64-linux/qemu-native/3.1.0-r0/qemu-3.1.0/linux-user/syscall.c:185:13: note: in definition of macro ‘_syscall0’
 185 | static type name (void)   \
 |             ^~~~
 In file included from /usr/include/unistd.h:1170,
 from TOPDIR/tmp/work/x86_64-linux/qemu-native/3.1.0-r0/qemu-3.1.0/include/qemu/osdep.h:90,
 from TOPDIR/tmp/work/x86_64-linux/qemu-native/3.1.0-r0/qemu-3.1.0/linux-user/syscall.c:20:
 /usr/include/bits/unistd_ext.h:34:16: note: previous declaration of ‘gettid’ was here
 34 | extern __pid_t gettid (void) __THROW;
 |                ^~~~~~

Signed-off-by: Armin Kuster <akuster808@gmail.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu/0001-linux-user-assume-__NR_gettid-always-exists.patch b/meta/recipes-devtools/qemu/qemu/0001-linux-user-assume-__NR_gettid-always-exists.patch
new file mode 100644
index 0000000000..767b200ba0
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0001-linux-user-assume-__NR_gettid-always-exists.patch
@@ -0,0 +1,49 @@
+From 184943d827ce09375284e6fbb9fd5eeb9e369529 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
+Date: Wed, 20 Mar 2019 16:18:41 +0000
+Subject: [PATCH] linux-user: assume __NR_gettid always exists
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+The gettid syscall was introduced in Linux 2.4.11. This is old enough
+that we can assume it always exists and thus not bother with the
+conditional backcompat logic.
+
+Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
+Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
+Reviewed-by: Laurent Vivier <laurent@vivier.eu>
+Message-Id: <20190320161842.13908-2-berrange@redhat.com>
+Signed-off-by: Laurent Vivier <laurent@vivier.eu>
+
+Upstream-Status: Backport
+dependancy patch for fix
+
+Signed-off-by: Armin Kuster <akuster808@gmail.com>
+
+---
+
+
+ linux-user/syscall.c | 8 --------
+ 1 file changed, 8 deletions(-)
+
+Index: qemu-3.0.0/linux-user/syscall.c
+===================================================================
+--- qemu-3.0.0.orig/linux-user/syscall.c
++++ qemu-3.0.0/linux-user/syscall.c
+@@ -251,15 +251,7 @@ static type name (type1 arg1,type2 arg2,
+ #define TARGET_NR__llseek TARGET_NR_llseek
+ #endif
+ 
+-#ifdef __NR_gettid
+ _syscall0(int, gettid)
+-#else
+-/* This is a replacement for the host gettid() and must return a host
+-   errno. */
+-static int gettid(void) {
+-    return -ENOSYS;
+-}
+-#endif
+ 
+ /* For the 64-bit guest on 32-bit host case we must emulate
+  * getdents using getdents64, because otherwise the host