
These files are taken from udunits, version 2.2.24.

The source files have been slightly modified in order to fit them into this
build system. The changes that were made are:

 - converter.h and udunits2.h include harp_udunits2_mangle.h to name mangle
   all public symbols.

 - scanner.l and parser.y have been renamed to utscanner.l and utparser.y

 - added options '%option prefix="harp_ut"' and '%option nounput' to
   utscanner.l

 - scanner.c is no longer included by parser.y resulting in the following
   additional changes:
   - _restartScanner is now a global variable named utrestartScanner
   - _isTime is now a non-static function named utisTime
   - #define yyparse utparse
   - #define yylex harp_utlex
   - #define yyerror harp_uterror
   - added ut_get_bufferpos function (returning yy_c_buf_p  - buf->yy_ch_buf)
   - added several function declarations to prevent compiler warnings

 - Added several casts to unsigned to eliminate 'comparison between signed
   and unsigned' warnings.

 - Fixed vector initialisation in ut_decode_time() in unticore.c.

 - Added '(void)variable;' entries in many functions to eliminate
  'unused parameter' warnings.

 - Made the following functions static: gregorianDateToJulianDay,
   julianDayToGregorianDate

 - Removed the following static functions since they were not used:
   utparser.y:clock_to_time()
   utparser.y:timezone_to_time()
   utparser.y:to_clock()
   unitcore.c:timestampNew()
   xml.c:startNoPlural()
   xml.c:endNoPlural()

 - use '_XOPEN_SOURCE 600' instead of '_XOPEN_SOURCE 500' to prevent
   warnings on Mac OS X.

 - Fixed spelling errors conform https://github.com/Unidata/UDUNITS-2/commit/8ecf9f48281eb86ec324ba339dc7a5d4c42b52e7
