Enable per-thread errno on Solaris
[trivial] Make rt.minfo import in object_.d function-local.

The 2.065 frontend trips over this when building the druntime
tests in shared library mode with LDC (forward reference to the
Object base class of TypeInfo when accessing the latter from
within rt.util.container). No idea why this happens, or why it
doesn't with DMD, but this fixes it and it also is a small
improvement on its own regardless.
test/*/Makefile: Do not assume that $(ROOT) is a relative path.

This allows us (LDC) to use the Makefiles in out-of-source builds.
Merge pull request #858 from klickverbot/test-out-of-source

test/*/Makefile: Do not assume that $(ROOT) is a relative path.
Merge pull request #857 from klickverbot/minfo-import

[trivial] Make rt.minfo import in object_.d function-local.
Mark core.sys.windows.windows.GetLastError as trusted
Merge pull request #861 from tom-tan/trusted-sys-windows-windows-GetLastError

Mark core.sys.windows.windows.GetLastError as trusted
Remove unused Thread.sm_clen variable.

It stored the size of the global context list, but that isn't used
explicitly anywhere.
Fix 12977 - lf64 definitions aren't correct on Solaris
Fix 12978 - struct sigaction is too small on 32-bit Solaris
Fix 13037 - SIGRTMIN and SIGRTMAX aren't correctly defined on Solaris
Merge pull request #859 from jasonbking/lf64

Multiple Solaris fixes
Added comment for -D_REENTRANT
Merge pull request #862 from klickverbot/remove-sm_clen

Remove unused Thread.sm_clen variable.
Merge pull request #860 from jasonbking/errno

Enable per-thread errno on Solaris