package/protozero: fix build with clang-tidy

Fix the following build failure if clang-tidy is found on host (and
protobuf is built before protozero) which is raised since tests are
disabled in commit be4869f393:

CMake Error at CMakeLists.txt:77 (add_dependencies):
  The dependency target "writer_tests" of target "clang-tidy" does not exist.

Fixes:
 - http://autobuild.buildroot.org/results/c3ae3b5caf79eb30c8a1786f58abea4f2b41a26e

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Reviewed-by: Maxim Kochetkov <fido_max@inbox.ru>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/protozero/0001-CMakeLists.txt-protobuf-is-only-needed-for-tests.patch

@@ -0,0 +1,35 @@
+From 1c16d3ffccd9e415c6ea3681f23231cd5184043c Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Wed, 16 Feb 2022 00:11:38 +0100
+Subject: [PATCH] CMakeLists.txt: protobuf is only needed for tests
+
+Don't check for protobuf if tests are disabled. As a side effect, this
+will avoid a build failure if clang-tidy and protobuf are found but
+tests are disabled
+
+Fix #109
+
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+[Upstream status: https://github.com/mapbox/protozero/pull/110]
+---
+ CMakeLists.txt | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index b975d49..df2ca15 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -52,7 +52,9 @@ endif()
+ #
+ #-----------------------------------------------------------------------------
+ 
+-find_package(Protobuf)
++if(BUILD_TESTING)
++    find_package(Protobuf)
++endif()
+ 
+ 
+ #-----------------------------------------------------------------------------
+-- 
+2.34.1
+