7.4.1 Cache Variable Names
The names of cache variables should have the following format:
     package-prefix_cv_value-type_specific-value_[additional-options]
   for example, `ac_cv_header_stat_broken' or
`ac_cv_prog_gcc_traditional'.  The parts of the variable name are:
     
- package-prefix
- An abbreviation for your package or organization; the same prefix you
begin local Autoconf macros with, except lowercase by convention. 
For cache values used by the distributed Autoconf macros, this value is
`ac'.
     
 
- _cv_
- Indicates that this shell variable is a cache value.  This string
must be present in the variable name, including the leading
underscore.
     
 
- value-type
- A convention for classifying cache values, to produce a rational naming
system.  The values used in Autoconf are listed in Macro Names.
     
 
- specific-value
- Which member of the class of cache values this test applies to. 
For example, which function (`alloca'), program (`gcc'), or
output variable (`INSTALL').
     
 
- additional-options
- Any particular behavior of the specific member that this test applies to. 
For example, `broken' or `set'.  This part of the name may
be omitted if it does not apply. 
The values assigned to cache variables may not contain newlines. 
Usually, their values are Boolean (`yes' or `no') or the
names of files or functions; so this is not an important restriction.