tlbuild: Build one engine

 
 4.6 Build one engine
 ====================
 
 Unfortunately, there is one common case where the steps in the preceding
 section to build one package (⇒Build one package) do not suffice:
 wanting to build one, or a subset, of the TeX engines (or other Web2c
 programs).
 
    The simplest way to do this is to disable everything and then
 explicitly specify what to make.  For example, to build only the
 original TeX:
 
      cd Work        # top build directory
      ../configure --without-x --disable-shared --disable-all-pkgs \
                   --enable-tex --disable-synctex -C CFLAGS=-g CXXFLAGS=-g
      make
      cd texk/web2c  # cd engine build directory
      make tex       # must specify target
 
    The first 'make' run will configure everything, and even build the
 libraries, even though the packages are disabled.  The source tree can
 be cut down to just what is needed for the given engine (the separate
 pdfTeX and LuaTeX source repositories do this, for example), but see
 caveats in previous section.
 
    If you want to debug an X-related program or shared library setup, or
 other variants, change the 'configure' options accordingly.  Either
 '../Build' or '../configure' can be run.
 
    Then it is necessary to again specify the target engine ('tex', in
 the above) in the 'make'.
 
    All this is somewhat unfortunate.  We hope to improve the situation
 in the future.  Patches are welcome.