Bug #32433090 RUN CLANG-TIDY MODERNIZE-USE-EQUALS-DEFAULT OVER THE CODE BASE [prerequisite]

Prerequisite patch to get a clean build with system protobuf.
Add cmake code to ignore -Wextra-semi warnings.

System protoc (on Fedora 33) is version 3.12.4 and generates things like:
  inline Expr() : Expr(nullptr) {};
whereas our bundled protoc is version 3.11.4 and generates
  Expr();
for the same input.

Change-Id: I0009d2f83406092ba3c4f9268997c262f1316bb3

Author: Tor Didriksen

unittest/gunit/xplugin/xcl/CMakeLists.txt

@@ -35,6 +35,12 @@ SET(XCL_UNIT_TESTS xclient_unit_tests)
 
 INCLUDE(source_files.cmake)
 
+# There may be extra semicolons in code generated by protobuf.
+MY_CHECK_CXX_COMPILER_WARNING("-Wextra-semi" HAS_WARN_FLAG)
+IF(HAS_WARN_FLAG)
+  STRING_APPEND(CMAKE_CXX_FLAGS " ${HAS_WARN_FLAG}")
+ENDIF()
+
 # This compiler fails to handle some of the mock functions involved.
 IF(MY_COMPILER_IS_SUNPRO)
   LIST(REMOVE_ITEM XCL_TEST_SRC

unittest/gunit/xplugin/xpl/CMakeLists.txt

@@ -30,6 +30,12 @@ SET(XPL_UNIT_TESTS xplugin_unit_tests)
 
 INCLUDE(source_files.cmake)
 
+# There may be extra semicolons in code generated by protobuf.
+MY_CHECK_CXX_COMPILER_WARNING("-Wextra-semi" HAS_WARN_FLAG)
+IF(HAS_WARN_FLAG)
+  STRING_APPEND(CMAKE_CXX_FLAGS " ${HAS_WARN_FLAG}")
+ENDIF()
+
 # This compiler fails to handle some of the mock functions involved.
 IF(MY_COMPILER_IS_SUNPRO)
   LIST(REMOVE_ITEM XPL_TEST_SRC