Avoid -Wmissing-field-initializers for Dl_info struct

Rely on the default initialization, this is arguably slightly less
clear, but allows to avoid the warning (which is disabled by default,
but still).

Closes #17997.

src/unix/dlunix.cpp

@@ -285,7 +285,7 @@ wxDynamicLibraryDetailsArray wxDynamicLibrary::ListLoaded()
 void* wxDynamicLibrary::GetModuleFromAddress(const void* addr, wxString* path)
 {
 #ifdef HAVE_DLADDR
-    Dl_info di = { 0 };
+    Dl_info di = { }; // 0 initialize whatever fields the struct has
 
     // At least under Solaris dladdr() takes non-const void*.
     if ( dladdr(const_cast<void*>(addr), &di) == 0 )