To prepare for completion of the [socket -async] implementation:
  *  Move the server code from CreateSocket to Tcl_OpenTcpServer.
  *  Rename CreateSocket to CreateClientSocket.
  *  Unify the naming convention of socket channels with Unix (sock + hex representation of the state/info structure).
merge trunk
Add compilations for the following commands:
 * concat
 * linsert
 * namespace origin
 * next
 * string replace
 * string tolower
 * string totitle
 * string toupper
 * string trim
 * string trimleft
 * string trimright
Make DEFAULT_TRIM_SET a MODULE_SCOPE string constant, so its value can be shared in tclCmdMZ.o and TclCompCmdsSZ.o 
and it no longer pollutes the tclStringTrim.h header file.
[2992970] Restore the safety of Tcl_AppendObjToObj(x, x) for bytearrays.
Also moves overflow checking to TclAppendBytesToByteArray() and adds
the ability to call TABTBA() with bytes==NULL, for appending unspecified
bytes.  That is, the string grows, but the new bytes are of undetermined
value.  Like Tcl_NewByteArrayObj(NULL, length) this option is useful
for manipulating buffers.  The TABTBA growth algorithm is also enhanced
a bit, copying over a fuller implementation from GrowStringBuffer()
in tclStringObj.c
[2992970] Restore safety of Tcl_AppendObjToObj(x, x) for bytearrays.
Silence compiler warnings.
merge mark
Backport of bytearray append machinery to support bug fixes in ReadBytes.
There is no need for ReadBytes() or its caller(s) to track how many bytes
are actually stored in objPtr.  The ByteArray Tcl_ObjType already has the
machinery to take care of this.
add compilation for [nextto] and [yieldto]; fix [a90d9331bc]
remove unused variable
improved tidy-up from branch
Eliminate the copy to a staging buffer when that serves no functional purpose.
In WriteChars(), eliminate the copy step through a staging buffer when
it is not required for channel translation.
In WriteChars(), eliminate the copy step through a staging buffer when it
is not required for channel translation.
merge 8.5
sync tcl.m4 with Tk version
sync tcl.m4 with Tk version
Revise the Tcl_Append* machinery to tolerate NULL bytes to append.
Then have ReadChars() use that machinery to resize buffer receiving input,
rather than invent its own version.  Simplify ReadChars() callers.