[PATCH] lttng-ust: fix do_compile failure for arm32 with DEBUG_BUILD enabled

From: Changqing Li <redacted>

After upgrade to 2.13.0, for arm32, with DEBUG_BUILD enabled, lttng-ust
build failed with error:
| /path/to/tmp/work/cortexa15t2hf-neon-poky-linux-gnueabi/lttng-ust/2_2.13.0-r0/recipe-sysroot-native/usr/bin/arm-poky-linux-gnueabi/../../libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/11.2.0/ld: ../../../src/lib/lttng-ust/.libs/liblttng-ust.so: undefined reference to `_uatomic_link_error'
| collect2: error: ld returned 1 exit status
| Makefile:399: recipe for target 'test_ust_error' failed
| make[3]: *** [test_ust_error] Error 1

The problem has reported to upstream, and upstream suggests to use
-DUATOMIC_NO_LINK_ERROR for the failure case, refer [1].

[1]https://lists.lttng.org/pipermail/lttng-dev/2021-September/030056.html

Signed-off-by: Changqing Li <redacted>
---
 meta/recipes-kernel/lttng/lttng-ust_2.13.0.bb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/meta/recipes-kernel/lttng/lttng-ust_2.13.0.bb b/meta/recipes-kernel/lttng/lttng-ust_2.13.0.bb
index 4ec92c0683..7c6a0743e1 100644
--- a/meta/recipes-kernel/lttng/lttng-ust_2.13.0.bb
+++ b/meta/recipes-kernel/lttng/lttng-ust_2.13.0.bb

@@ -16,6 +16,7 @@ inherit autotools lib_package manpages python3native pkgconfig
 include lttng-platforms.inc
 
 EXTRA_OECONF = "--disable-numa"
+CPPFLAGS:append:arm = "${@oe.utils.vartrue('DEBUG_BUILD', '-DUATOMIC_NO_LINK_ERROR', '', d)}"
 
 DEPENDS = "liburcu util-linux"
 RDEPENDS:${PN}-bin = "python3-core"

-- 
2.17.1