manual: Update _TIME_BITS to clarify it's user defined

The current language reads "This macro determines...", changing to
"Define this macro...".  This is consistent with other feature macro
documentation language.

When I first read the previous language it seems to indicate that the
macro is already defined.  By changing the language to "Define this
macro..." it's clear that its the user's responsibility to define it.

diff --git a/manual/creature.texi b/manual/creature.texi
index c13de52..6193e07 100644 (file)
--- a/manual/creature.texi
+++ b/manual/creature.texi
@@ -171,8 +171,8 @@ This macro was introduced as part of the Large File Support extension
 @end defvr
 
 @defvr Macro _TIME_BITS
-This macro determines the bit size of @code{time_t}, and therefore the
-bit size of all @code{time_t}-derived types and the prototypes of all
+Define this macro to control the bit size of @code{time_t}, and therefore
+the bit size of all @code{time_t}-derived types and the prototypes of all
 related functions.
 
 @enumerate