pgsql: Make init_spin_delay() C89 compliant #2.

Make init_spin_delay() C89 compliant #2.

My previous attempt at doing so, in 80abbeba23, was not sufficient. While that
fixed the problem for bufmgr.c and lwlock.c , s_lock.c still has non-constant
expressions in the struct initializer, because the file/line/function
information comes from the caller of s_lock().

Give up on using a macro, and use a static inline instead.

Discussion: 4369(dot)1460435533(at)sss(dot)pgh(dot)pa(dot)us

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/4b74c6a40e7ac9dad7cdeb4cfd2d51ea60cfdbb5

Modified Files
--------------
src/backend/storage/buffer/bufmgr.c | 8 ++++++--
src/backend/storage/lmgr/lwlock.c | 4 +++-
src/backend/storage/lmgr/s_lock.c | 4 +++-
src/include/storage/s_lock.h | 15 +++++++++++++--
4 files changed, 25 insertions(+), 6 deletions(-)