#3437 Glob-magic in clock format string

[Kaitzschu]

% info patchlevel
8.5a5
% clock format 0 -format {}
% clock format 0 -format *
invalid command name "::tcl::clock::formatproc'*'C"

This comes from parseClockFormatFormat where existence
of previous formatter is checked with
if {[info procs $procName] != {}} {
which finds everything (with *). Can be fixed with
if {$procName in [info procs "formatproc*"]} {
which doesn't use glob-magic. Usage of 8.5 "in"
operator seems appropriate since new clock isn't being
backported.

[Don Porter]

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user_id=80530

[namespace which] makes
a good alternative to
[info commands] when one
command is sought that might
contain glob-special chars.