when building _tkinter.  configure has two new options; if used, both must
be specified:

  ./configure \
      --with-tcltk-includes="-I/opt/local/include" \
      --with-tcltk-libs="-L/opt/local/lib -ltcl8.5 -ltk8.5"

In addition, the options can be overridden with make:

   make \
       TCLTK_INCLUDES="-I/opt/local/include" \
       TCLTK_LIBS="-L/opt/local/lib -ltcl8.6 -ltk8.6"

  two makefile macros SHLIB_SUFFIX and EXT_SUFFIX. SO now has the value of
  SHLIB_SUFFIX again (as in 2.x and 3.1). The SO macro is removed in 3.4.

  db-5.x, and dropping support for db-4.1 and db-4.2.

when it needs support from timemodule (which is a .so on linux):
link in timemodule.c for the required functions.

  the package.

defined in cross compiling mode, too.

not source directory.

Patch by Richard Oudkerk (sbt).

  tools (dpkg-dev) installed.

  tools (dpkg-dev) installed.

  tools (dpkg-dev) installed.

Also add tests in the OS X installer build to ensure that the desired
dynamic linking with an optional newer Tcl/Tk in /Library actually
happens.

  from GCC for native builds

  for host compiler.

set cross_compiling = False for now.