Log Message:
-----------
Handle missing M_PI the same way we've been doing in the core code,
instead of inserting an MSVC dependency.
Modified Files:
--------------
pgsql/contrib/earthdistance:
earthdistance.c (r1.12 -> r1.13)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/earthdistance/earthdistance.c.diff?r1=1.12&r2=1.13)