oe-selftest: add a cpp-example recipe

This simple C++ project supports compilation with CMake and Meson.
(Autotool support could be added later on.)
It's supposed to be used with oe-selftest.

An artificial project has several advantages over compiling a normal
CMake or Meson based project for testing purposes:
- It is much faster because it can be kept minimalistic
- It can cover multiple odd corner cases
- No one will change it in an unpredictable way
- It can support multiple build tools with only one C++ codebase

(From OE-Core rev: 4904e772470b0d6e5d98ef0344b3f2bf54214661)

Signed-off-by: Adrian Freihofer <adrian.freihofer@siemens.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-selftest/recipes-test/cpp/cpp-example.inc

@@ -0,0 +1,24 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: MIT
+#
+
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
+
+DEPENDS += "json-c"
+
+PV = "1.0"
+
+SRC_URI = "\
+    file://cpp-example.cpp \
+    file://cpp-example-lib.hpp \
+    file://cpp-example-lib.cpp \
+    file://test-cpp-example.cpp \
+    file://run-ptest \
+"
+
+S = "${WORKDIR}"
+
+inherit ptest