Previous logic would only create it when pkg-config was in USE_TOOLS,
but pkg-config is not the only tool that uses them - for example any
package that uses ruby-pkg-config. Fixes graphics/ruby-cairo.
* __uuid_generate_time() report if clock_seq is safe
* do not use invalid file descriptor
* fix test in get_clock()
* get_clock() report if the clock_seq is safe
* introduce uuid_generate_time_safe()
* manpage spelling fixes
* move __uuid function to UUIDD_PRIVATE in uuid.sym
* rename uuid__generate_* to __uuid_generate_*
* update manpage, mention uuid_generate_time_safe