BUG #1369: RC3 Compilation fails on mingw

The following bug has been logged online:

Bug reference:      1369
Logged by:          T.J.
Email address:      tjtoocool@phreaker.net
PostgreSQL version: 8.0
Operating system:   Windows XP
Description:        RC3 Compilation fails on mingw
Details: 

Tested RC2 and RC3 --with-openssl configured. RC2 makes and installs fine.
RC3, however, has this to say when trying make:

gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement         -Wold-style-definition -Wendif-labels
-fno-strict-aliasing   -DFRONTEND -I../..       
/../../src/interfaces/ecpg/include -I../../../../src/interfaces/libpq
-I../../..        /../src/port -I../../../../src/include
-I./src/include/port/win32 -DEXEC_BACKEND         
"-I../../../../src/include/port/win32" -DBUILDING_DLL  -c -o path.o path.c
path.c: In function `get_share_path':
path.c:375: error: `PGSHAREDIR' undeclared (first use in this function)
path.c:375: error: (Each undeclared identifier is reported only once
path.c:375: error: for each function it appears in.)
path.c:375: error: `PGBINDIR' undeclared (first use in this function)
path.c: In function `get_etc_path':
path.c:384: error: `PGBINDIR' undeclared (first use in this function)
path.c: In function `get_include_path':
path.c:393: error: `INCLUDEDIR' undeclared (first use in this function)
path.c:393: error: `PGBINDIR' undeclared (first use in this function)
path.c: In function `get_pkginclude_path':
path.c:402: error: `PKGINCLUDEDIR' undeclared (first use in this function)
path.c:402: error: `PGBINDIR' undeclared (first use in this function)
path.c: In function `get_includeserver_path':
path.c:411: error: `INCLUDEDIRSERVER' undeclared (first use in this
function)
path.c:411: error: `PGBINDIR' undeclared (first use in this function)
path.c: In function `get_lib_path':
path.c:420: error: `LIBDIR' undeclared (first use in this function)
path.c:420: error: `PGBINDIR' undeclared (first use in this function)
path.c: In function `get_pkglib_path':
path.c:429: error: `PKGLIBDIR' undeclared (first use in this function)
path.c:429: error: `PGBINDIR' undeclared (first use in this function)
path.c: In function `get_locale_path':
path.c:438: error: `LOCALEDIR' undeclared (first use in this function)
path.c:438: error: `PGBINDIR' undeclared (first use in this function)
make[4]: *** [path.o] Error 1
make[4]: Leaving directory
`/c/postgresql-8.0.0rc3/src/interfaces/ecpg/ecpglib'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/c/postgresql-8.0.0rc3/src/interfaces/ecpg'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/c/postgresql-8.0.0rc3/src/interfaces'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/c/postgresql-8.0.0rc3/src'
make: *** [all] Error 2