BUG #3769: Fail to make bcc32.mak for libpq

The following bug has been logged online:

Bug reference: 3769
Logged by: CN
Email address: cnliou9(at)fastmail(dot)fm
PostgreSQL version: 8.3beta3
Operating system: Win 98
Description: Fail to make bcc32.mak for libpq
Details:

MAKE Version 5.2 Copyright (c) 1987, 2000 Borland
Building the Win32 DLL and Static Library...

No configuration specified. Defaulting to Release.

copy ..\..\include\pg_config.h.win32 ..\..\include\pg_config.h
1 file(s) copied
echo #define SYSCONFDIR "" > pg_config_paths.h
bcc32.exe
-I\borland\bcc55\include;..\..\include;..\..\include\port\win32;..\..\includ
e\port\win32_msvc;..\..\port -n".\Release" -WD -c
-DFRONTEND;NDEBUG;WIN32;_WINDOWS -tWM -a8 -X -w-use -w-par -w-pia -w-csu
-w-aus -w-ccc -O -Oi -OS -DNDEBUG win32.c
Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland
win32.c:
Error E2209 ..\..\include\c.h 88: Unable to open include file
'pg_config_os.h'
*** 1 errors in Compile ***

** error 1 ** deleting ".\Release\win32.obj"