Log Message:
Changes 8.4.12:
  * Repeated [namespace import] of same command now permitted.
  * ${prefix}/share added to ::tcl_pkgPath on some systems.
  * [exec]'s >> redirection has improved append behavior.
  * [info globals] returned only existing variables.
  * Recognize some Solaris variations of the cp1251 encoding.
  * Addressed [file mkdir] race condition.
  * Support opening >2GB files on RHEL 3.
  * Corrections to $argv formatting when [encoding system] is multibyte.
  * http 2.5.2: Update URL encoding rules to RFC 3986.
  * Fixed issue in recursive file delete with NFS lock files.
  * Stopped crash after use of Tcl_TraceCommand().
  * Win NT/XP: support unicode console.
  * Improved support for Tclkit to set [encoding system].
  * Added Korean timezone abbreviations.
  * Windows: exit codes can now exceed -128..127 range.
  * [load] support on LynxOS.
  * Packages with incorrect index scripts now cause a warning to be logged.
        *** POTENTIAL INCOMPATIBILITY ***
  * [lsearch -regexp] now accepts backrefs in the RE.
  * [selection get] made compatible with OpenOffice.org.
  * Dialog support for widget names containing spaces.
  * Improved Tk window manager event interaction on OS X Aqua.