syslog fix

Since logging with syslog is a documented feature, we need to fix it
anyway, IMHO. Here is a proposed fix for "too long message" problem of
syslog.

Included patches do followings:

o modifies write_syslog in utils/misc/trace.c

o if the message is too long (currently longer than 128 bytes), then
divides into smaller message segments. "128" would be probably too
small for some platforms, but I don't how long is the actual safe
limit of syslog messages on particular platform (seems 512 is safe on
Linux, for example).

o division of the message is carefully done so that it does not break
the word boundary.

o each message is prefixed with [logid-seq] where logid is incremented
at each write_syslog call, and seq is incremented at each syslog call
within a write_syslog call. This will prevent syslog to suppress
"same" messages.

o tested on Linux (RH4.2) and FreeBSD 4.0.

Comments are welcome....
--
Tatsuo Ishii

BTW, here are some examples from actual syslog messages:

May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-1] NOTICE: QUERY DUMP: { SEQSCAN :startup_cost 0.00 :total_cost 3.22 :rows 122 :width 81 :state <> :qptargetlist ({ TARGETENTRY
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-2] :resdom { RESDOM :resno 1 :restype 19 :restypmod -1 :resname typname :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false }
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-3] :expr { VAR :varno 1 :varattno 1 :vartype 19 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 1}} { TARGETENTRY :resdom {
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-4] RESDOM :resno 2 :restype 23 :restypmod -1 :resname typowner :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr {
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-5] VAR :varno 1 :varattno 2 :vartype 23 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 2}} { TARGETENTRY :resdom { RESDOM
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-6] :resno 3 :restype 21 :restypmod -1 :resname typlen :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-7] 1 :varattno 3 :vartype 21 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 3}} { TARGETENTRY :resdom { RESDOM :resno 4
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-8] :restype 21 :restypmod -1 :resname typprtlen :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-9] :varattno 4 :vartype 21 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 4}} { TARGETENTRY :resdom { RESDOM :resno 5
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-10] :restype 16 :restypmod -1 :resname typbyval :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-11] :varattno 5 :vartype 16 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 5}} { TARGETENTRY :resdom { RESDOM :resno 6
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-12] :restype 18 :restypmod -1 :resname typtype :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-13] :varattno 6 :vartype 18 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 6}} { TARGETENTRY :resdom { RESDOM :resno 7
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-14] :restype 16 :restypmod -1 :resname typisdefined :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-15] :varattno 7 :vartype 16 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 7}} { TARGETENTRY :resdom { RESDOM :resno 8
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-16] :restype 18 :restypmod -1 :resname typdelim :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-17] :varattno 8 :vartype 18 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 8}} { TARGETENTRY :resdom { RESDOM :resno 9
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-18] :restype 26 :restypmod -1 :resname typrelid :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-19] :varattno 9 :vartype 26 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 9}} { TARGETENTRY :resdom { RESDOM :resno 10
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-20] :restype 26 :restypmod -1 :resname typelem :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-21] :varattno 10 :vartype 26 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 10}} { TARGETENTRY :resdom { RESDOM :resno 11
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-22] :restype 24 :restypmod -1 :resname typinput :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-23] :varattno 11 :vartype 24 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 11}} { TARGETENTRY :resdom { RESDOM :resno 12
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-24] :restype 24 :restypmod -1 :resname typoutput :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-25] :varattno 12 :vartype 24 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 12}} { TARGETENTRY :resdom { RESDOM :resno 13
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-26] :restype 24 :restypmod -1 :resname typreceive :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-27] :varattno 13 :vartype 24 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 13}} { TARGETENTRY :resdom { RESDOM :resno 14
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-28] :restype 24 :restypmod -1 :resname typsend :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-29] :varattno 14 :vartype 24 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 14}} { TARGETENTRY :resdom { RESDOM :resno 15
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-30] :restype 18 :restypmod -1 :resname typalign :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-31] :varattno 15 :vartype 18 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 15}} { TARGETENTRY :resdom { RESDOM :resno 16
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-32] :restype 25 :restypmod -1 :resname typdefault :reskey 0 :reskeyop 0 :ressortgroupref 0 :resjunk false } :expr { VAR :varno 1
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-33] :varattno 16 :vartype 25 :vartypmod -1 :varlevelsup 0 :varnoold 1 :varoattno 16}}) :qpqual <> :lefttree <> :righttree <>
May 23 10:58:51 srapc968-yotsuya postgres[9902]: [1-34] :extprm () :locprm () :initplan <> :nprm 0 :scanrelid 1 }
May 23 10:58:51 srapc968-yotsuya postgres[9902]: NOTICE: QUERY PLAN: Seq Scan on pg_type (cost=0.00..3.22 rows=122 width=81)