Fix for clashing #defines of ERROR

This fixes clashing defines of ERROR. On win32, winapi.h is included, which
includes windows.h, which #defines ERROR to 0. PostgreSQL's logging functions
define ERROR to -1. This patch redefines ERROR to -1 to avoid current or
future breakage of the logging functions.

Gerhard
--
mail:   gerhard <at> bigfoot <dot> de       registered Linux user #64239
web:    http://www.cs.fhm.edu/~ifw00065/    public key at homepage
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reduce(lambda x,y:x+y,map(lambda x:chr(ord(x)^42),tuple('zS^BED\nX_FOY\x0b')))
diff -N -r -C3 --exclude=CVS ../pgsql_HEAD/src/include/libpq/pqcomm.h ./src/include/libpq/pqcomm.h
*** ../pgsql_HEAD/src/include/libpq/pqcomm.h    Mon Aug 27 20:43:58 2001
--- ./src/include/libpq/pqcomm.h    Mon Aug 27 20:46:56 2001
***************
*** 19,24 ****
--- 19,28 ----
  #include <sys/types.h>
  #ifdef WIN32
  #include <winsock.h>
+ /* workaround for clashing defines of "ERROR" */
+ #ifdef ELOG_H
+ #define ERROR    (-1)
+ #endif
  #else                            /* not WIN32 */
  #include <sys/socket.h>
  #ifdef HAVE_SYS_UN_H