qemu: fix do_compile error

Fix error like:
Fatal error: can't create tests/ptimer-test.p/..._qemu-5.2.0_hw_core_ptimer.c.o: File name too long

(From OE-Core rev: e125430dea6e5eba5587f56602b006c90ab16509)

Signed-off-by: Changqing Li <changqing.li@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/qemu/qemu.inc

@@ -29,6 +29,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
            file://mingwfix.patch \
            file://mmap.patch \
            file://mmap2.patch \
+           file://0001-tests-meson.build-use-relative-path-to-refer-to-file.patch \
            "
 UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
 

meta/recipes-devtools/qemu/qemu/0001-tests-meson.build-use-relative-path-to-refer-to-file.patch

@@ -0,0 +1,34 @@
+From a4bdc0416134477e4eae386db04b1de7491163bb Mon Sep 17 00:00:00 2001
+From: Changqing Li <changqing.li@windriver.com>
+Date: Thu, 14 Jan 2021 06:33:04 +0000
+Subject: [PATCH] tests/meson.build: use relative path to refer to files
+
+Fix error like:
+Fatal error: can't create tests/ptimer-test.p/..._qemu-5.2.0_hw_core_ptimer.c.o: File name too long
+
+when build path is too long, use meson.source_root() will make this
+filename too long. Fixed by using relative path to refer to files
+
+Upstream-Status: Submitted [send to qemu-devel]
+
+Signed-off-by: Changqing Li <changqing.li@windriver.com>
+---
+ tests/meson.build   | 2 +-
+ 1 files changed, 1 insertions(+), 1 deletion(-)
+
+diff --git a/tests/meson.build b/tests/meson.build
+index afeb6be..54684b5 100644
+--- a/tests/meson.build
++++ b/tests/meson.build
+@@ -113,7 +113,7 @@ tests = {
+   'test-keyval': [testqapi],
+   'test-logging': [],
+   'test-uuid': [],
+-  'ptimer-test': ['ptimer-test-stubs.c', meson.source_root() / 'hw/core/ptimer.c'],
++  'ptimer-test': ['ptimer-test-stubs.c', '../hw/core/ptimer.c'],
+   'test-qapi-util': [],
+ }
+ 
+-- 
+2.29.2
+