systemc: Get rid of leftovers from unimplemented warnings past.

These warnings were removed when the functionality they warned about
was implemented, but there were some leftovers like unnecessary
includes and some helper functions which hid gem5 specific headers
from the ext directory.

Change-Id: Ic886ac0f1264687524e3a7b7eaab8836f318a5a2
Reviewed-on: https://gem5-review.googlesource.com/c/13398
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Implement general and VCD trace support.

This doesn't include WIF trace support, but does make allowances for
adding it in the future.

Change-Id: Ifb62f40a7d8a13e94463930a44ac4b1cf41e3009
Reviewed-on: https://gem5-review.googlesource.com/c/12826
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add the deprecated sc_trace_delta_cycles function.

This function enables or disables tracing of delta cycles in a
particular trace file.

Change-Id: I53164a792856d071de1fefc76977cca8eb5fd735
Reviewed-on: https://gem5-review.googlesource.com/11267
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add nonstandard sc_trace-s for sc_event and sc_time.

These are not in the standard but are defined by Accellera and are
used in the regression tests.

Change-Id: Idb8358530b1135526c52733e628461a17308e216
Reviewed-on: https://gem5-review.googlesource.com/11259
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add some non-standard sc_trace variants.

These overloads of sc_trace take the unsigned version of some primitive
types. The compiler thought it was ambiguous how to convert an unsigned
integer value into a signed one since there were several different
functions which took signed integer parameters of various sizes.

These versions of sc_trace aren't in the standard, but they are in the
Accellera implementation and do fix building of the regression tests.

Change-Id: I26fd06d90ae6bf5fc5aed24bc2ac826ad69eee31
Reviewed-on: https://gem5-review.googlesource.com/11182
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Stub out all the standard utilility classes and functions.

Change-Id: I9e9724edb6281e0b0a6bae5546b0ede77d295c12
Reviewed-on: https://gem5-review.googlesource.com/10841
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>