This package and the next two are only installed to be able to run the test suites for GCC and Binutils. Installing three packages just for testing purposes may seem like overkill, but it is very reassuring, if not essential, to know that our most important tools are working properly. Prepare Tcl to be compiled: cd unix ./configure --prefix=/tools Build the package: make This package has a test suite available which can perform a number of checks to ensure it built correctly. However, the Tcl test suite here in Chapter 5 is known to experience failures under certain host conditions that are not fully understood. Therefore, test suite failures here are not surprising, but are not considered critical. Should you choose to run the test suite, the following command will do so: TZ=UTC make test The meaning of the make option: TZ=UTC: This sets the time zone to Coordinated Universal Time (UTC) also known as Greenwich Mean Time (GMT), but only for the duration of the test suite run. This ensures the clock tests are exercised correctly. More information on the TZ environment variable is available later on in Chapter 7. Sometimes, package test suites will give false failures. You can consult the LFS Wiki at to verify that these failures are normal. This applies to all tests throughout the book. Install the package: make install Do not remove the tcl&tcl-version; source directory yet, as the next package will need its internal headers. Make a necessary symbolic link: ln -s tclsh8.4 /tools/bin/tclsh