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

    - Enables invoking the default constructor for a field when
      constructing a field-based channel

    - Used to indicate an empty vector when constructing field-based
      protocol channels

    - Creates an enum class with the necessary members to use an enum
      with EnumArray
    - Includes optional automatic print function generation
Fix cppcheck warnings
Add field-based channel protocols
Convert TileLink to field-based channel protocol

Fix Python Error By Adding Main Function

Upstream latest updates

NOPs when non-user skipping is enabled

Add instruction index (instIndex()) and unskipped instruction index (unskippedInstIndex()) to STFBranch
    - Instruction index = index of branch when using STFInstReader with
      same non-user skipping mode
    - Unskipped instruction index = index of branch when using
      STFInstReader with no skipping enabled