Fixed two critical issues from the rebase:
1. Added LIBIPC_OS_FREEBSD macro definition in detect_plat.h to enable
FreeBSD platform detection alongside other OS checks
2. Added missing #include "libipc/imp/detect_plat.h" in detail.h to
properly include platform detection macros
These fixes ensure FreeBSD compilation will work correctly with the
unified platform detection system.
IMPROVEMENTS:
1. Add explicit zero-argument overload to avoid SFINAE ambiguity
2. Require at least one argument (A1) for parameterized overloads
3. Better separation between direct initialization and aggregate initialization
BENEFITS:
- Clearer intent: zero-argument construction is explicitly handled
- Avoids potential SFINAE ambiguity when empty parameter pack is used
- More maintainable: easier to understand which overload is selected
- Consistent with modern C++ best practices for variadic templates
TECHNICAL DETAILS:
- Zero-arg overload: Always uses T() for value initialization
- One-or-more-arg overload: Uses SFINAE to choose between:
* T(args...) for types with matching constructor
* T{args...} for aggregate types or types with initializer_list ctor
This is a code quality improvement and does not fix any compilation issues,
but provides better template overload resolution.
