FindTCL

TK_INTERNAL_PATH 已删除。

此模块查找 Tcl 是否已安装，并确定头文件和库所在的位置。它还确定库的名称。此代码设置以下变量

TCL_FOUND              = Tcl was found
TK_FOUND               = Tk was found
TCLTK_FOUND            = Tcl and Tk were found
TCL_LIBRARY            = path to Tcl library (tcl tcl80)
TCL_INCLUDE_PATH       = path to where tcl.h can be found
TCL_TCLSH              = path to tclsh binary (tcl tcl80)
TK_LIBRARY             = path to Tk library (tk tk80 etc)
TK_INCLUDE_PATH        = path to where tk.h can be found
TK_WISH                = full path to the wish executable

为了消除一些混乱并解决并非一定是 Tcl/Tk 大师/开发人员人员遇到的一些问题，一些变量已被移动或删除。与 CMake 2.4 相比，变更情况是

=> they were only useful for people writing Tcl/Tk extensions.
=> these libs are not packaged by default with Tcl/Tk distributions.
   Even when Tcl/Tk is built from source, several flavors of debug libs
   are created and there is no real reason to pick a single one
   specifically (say, amongst tcl84g, tcl84gs, or tcl84sgx).
   Let's leave that choice to the user by allowing him to assign
   TCL_LIBRARY to any Tcl library, debug or not.
=> this ended up being only a Win32 variable, and there is a lot of
   confusion regarding the location of this file in an installed Tcl/Tk
   tree anyway (see 8.5 for example). If you need the internal path at
   this point it is safer you ask directly where the *source* tree is
   and dig from there.