Deprecated POD usage to be C++20 compatible

stfpy: Fixed wrong __next__ implementation

Fix compiler errors related to using an incomplete type with an std::unique_ptr

    - Deleter is malformed unless the destructor is defined in the
      STFReaderBase .cpp file

Iterator was falsely advanced every time before accessed. So the first record will be always ignored. Moreover, segmentation fault will be raised if the container is empty.

Tweak stfpy build/install flow to work better with in a conda packaging enivronment

environment

Properly handle ProcessIDExtRecord in STFWriter

Make open() and close() methods of STFFstream (and all subclasses) thread-safe

thread-safe

Check for PTE-related trace features in the header before constructing a PTE reader

PTE reader

Allow missing operand data in STFBranchReader

    - Default to 0 if there aren't any InstRegRecords attached to the
      instruction
    - stf_branch_hdf5 is the only tool that uses them right now

GCC Fixes

for fields with custom formatters

determine if types are eligible for use with PackedContainer

pack are POD

Clang
    - Otherwise GCC complains with a warning message

Fix segfault when trying to read a trace without PTEs

Rework ProcessIDExtRecord

    - Remove ASID and TGID
    - Add hardware thread ID
        - In an SMT context, corresponds to a single SMT hardware thread
        - In a non-SMT context, corresponds to a single core
    - Reorder fields:
        - First is HW TID
        - Second is PID
        - Third is TID

Disable LD version detection on macOS

Allow FORCE_PC records outside the header

Fix compiler error when -fvisibility-inlines-hidden is included in flags

Fixes #20

LD version check fixes

    - Use $LD environment variable if it's defined
    - Use a more permissive regex (RHEL-like systems append .el* to the
      end of the version string)

Check ld version and use it for LTO linking if it is v2.21 or newer

Upstream master

    Replace ADD_ARRAY_FIELD with FIELD_SPECIALIZATION macro
    Add OVERRIDE_FIELD_NAME macro