UNIX dependent features and general utilities in PHCv2.

New in this release is the inclusion of test programs (prefix "ts_").

--------------------------------------------------------------------------------
file name                 : short description
--------------------------------------------------------------------------------
natural_io                : instantiation of text_io with natural
integer_io                : instantiation of text_io with integer
unix_resource_usage       : auxiliary package for timing
timing_package            : measures usage of computing resources
sun_timing_package        : particular implementation for SunSparc Solaris
other_timing_package      : implementation for IBM RS/6000, Dec/Ultrix
system_call               : allows to execute UNIX system commands
machines                  : specific system calls
unix_command_line         : handling arguments on the command line
bye_bye_message           : message at the end of the program
communications_with_user  : dialogue to manipulate files, choose options
file_scanning             : scanning a file for text banners
--------------------------------------------------------------------------------
ts_timer                  : timing of summation of natural numbers
ts_syscall                : execution of a system call : "ls"
ts_mach                   : prints system information of current process
ts_cmdline                : prints the arguments of the command line
ts_byemess                : prints the message at the end of the program
ts_commuser               : tests the dialogues with the user
ts_filescan               : reads a file name and banner, and scans for it
--------------------------------------------------------------------------------

The timing package comes in two implementations.  The current one is linked
to the package that must be used on SunSparc Solaris machines.
For IBM RS/6000 and Dec/Ultrix, use the other implementation.

A package like Unix_Command_Line is available in some form in most Ada
compiling systems.  For encapsulation purposes it is included here.

The file scanning operations are part of the database management of the
system input files to PHC.

There are 28 files in this directory: besides the READ_ME file, 10 files
are specifications (ads), the other 17 files are implementations (adb).
wc *adb counts 1695 lines of Ada code