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Adding New Functions
====================

   The process of building the library is driven by the makefiles, which
make heavy use of special features of GNU `make'.  The makefiles are
very complex, and you probably don't want to try to understand them.
But what they do is fairly straightforward, and only requires that you
define a few variables in the right places.

   The library sources are divided into subdirectories, grouped by
topic.

   The `string' subdirectory has all the string-manipulation functions,
`math' has all the mathematical functions, etc.

   Each subdirectory contains a simple makefile, called `Makefile',
which defines a few `make' variables and then includes the global
makefile `Rules' with a line like:

     include ../Rules

The basic variables that a subdirectory makefile defines are:

`subdir'
     The name of the subdirectory, for example `stdio'.  This variable
     *must* be defined.

`headers'
     The names of the header files in this section of the library, such
     as `stdio.h'.

`routines'
`aux'
     The names of the modules (source files) in this section of the
     library.  These should be simple names, such as `strlen' (rather
     than complete file names, such as `strlen.c').  Use `routines' for
     modules that define functions in the library, and `aux' for
     auxiliary modules containing things like data definitions.  But the
     values of `routines' and `aux' are just concatenated, so there
     really is no practical difference.

`tests'
     The names of test programs for this section of the library.  These
     should be simple names, such as `tester' (rather than complete file
     names, such as `tester.c').  `make tests' will build and run all
     the test programs.  If a test program needs input, put the test
     data in a file called `TEST-PROGRAM.input'; it will be given to
     the test program on its standard input.  If a test program wants
     to be run with arguments, put the arguments (all on a single line)
     in a file called `TEST-PROGRAM.args'.  Test programs should exit
     with zero status when the test passes, and nonzero status when the
     test indicates a bug in the library or error in building.

`others'
     The names of "other" programs associated with this section of the
     library.  These are programs which are not tests per se, but are
     other small programs included with the library.  They are built by
     `make others'.

`install-lib'
`install-data'
`install'
     Files to be installed by `make install'.  Files listed in
     `install-lib' are installed in the directory specified by `libdir'
     in `configparms' or `Makeconfig' (Note: Installation).  Files
     listed in `install-data' are installed in the directory specified
     by `datadir' in `configparms' or `Makeconfig'.  Files listed in
     `install' are installed in the directory specified by `bindir' in
     `configparms' or `Makeconfig'.

`distribute'
     Other files from this subdirectory which should be put into a
     distribution tar file.  You need not list here the makefile itself
     or the source and header files listed in the other standard
     variables.  Only define `distribute' if there are files used in an
     unusual way that should go into the distribution.

`generated'
     Files which are generated by `Makefile' in this subdirectory.
     These files will be removed by `make clean', and they will never
     go into a distribution.

`extra-objs'
     Extra object files which are built by `Makefile' in this
     subdirectory.  This should be a list of file names like `foo.o';
     the files will actually be found in whatever directory object
     files are being built in.  These files will be removed by
     `make clean'.  This variable is used for secondary object files
     needed to build `others' or `tests'.