The names of cache variables should have the following format:
for example, ‘ac_cv_header_stat_broken’ or ‘ac_cv_prog_gcc_traditional’. The parts of the variable name are:
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’.
Indicates that this shell variable is a cache value. This string must be present in the variable name, including the leading underscore.
A convention for classifying cache values, to produce a rational naming system. The values used in Autoconf are listed in Macro Names.
Which member of the class of cache values this test applies to. For example, which function (‘alloca’), program (‘gcc’), or output variable (‘INSTALL’).
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. Cache Variable Index for an index of cache variables with documented semantics.