all: pacify clang-tidy, CI and cmake updates

src/check/dt_cxxlib.cpp

@@ -261,8 +261,8 @@ struct Z2_X2 : public X2 {
 **************************************************************************/
 
 TEST_CASE("Deleter") {
-    LE16 *o = {}; // object
-    LE32 *a = {}; // array
+    LE16 *o = nullptr; // object
+    LE32 *a = nullptr; // array
     {
         const upx::ObjectDeleter<LE16 **> o_deleter{&o, 1};
         o = new LE16;

src/pefile.cpp

@@ -1239,6 +1239,7 @@ void PeFile::Export::build(char *newbase, unsigned newoffs) {
 
     edir.addrtable = newoffs + ptr_diff_bytes(functionp, newbase);
     edir.ordinaltable = newoffs + ptr_diff_bytes(ordinalp, newbase);
+    assert(ordinals != nullptr); // pacify clang-tidy
     memcpy(ordinalp, ordinals, 2 * edir.names);
 
     edir.name = newoffs + ptr_diff_bytes(enamep, newbase);

src/util/cxxlib.h

@@ -179,7 +179,7 @@ forceinline Result ptr_static_cast(const From *ptr) noexcept {
     return static_cast<Result>(static_cast<const void *>(ptr));
 }
 
-// helper classes so we don't leak memory on exceptions
+// helper classes so we don't leak memory on exceptions; NOT thread-safe
 template <class T> // T is "Type **"
 struct ObjectDeleter final {
     static_assert(std::is_pointer_v<T>);