build: Enable some commonly enabled compiler diagnostics

Author: practicalswift

configure.ac

@@ -404,6 +404,10 @@ if test "x$CXXFLAGS_overridden" = "xno"; then
   AX_CHECK_COMPILE_FLAG([-Wdate-time],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wdate-time"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wconditional-uninitialized],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wconditional-uninitialized"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wsign-compare],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wsign-compare"],,[[$CXXFLAG_WERROR]])
+  AX_CHECK_COMPILE_FLAG([-Wduplicated-branches],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wduplicated-branches"],,[[$CXXFLAG_WERROR]])
+  AX_CHECK_COMPILE_FLAG([-Wduplicated-cond],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wduplicated-cond"],,[[$CXXFLAG_WERROR]])
+  AX_CHECK_COMPILE_FLAG([-Wlogical-op],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wlogical-op"],,[[$CXXFLAG_WERROR]])
+  AX_CHECK_COMPILE_FLAG([-Woverloaded-virtual],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Woverloaded-virtual"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wsuggest-override],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wsuggest-override"],,[[$CXXFLAG_WERROR]],
                         [AC_LANG_SOURCE([[struct A { virtual void f(); }; struct B : A { void f() final; };]])])
   AX_CHECK_COMPILE_FLAG([-Wunreachable-code-loop-increment],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wunreachable-code-loop-increment"],,[[$CXXFLAG_WERROR]])