Cannot build latest snapshot under Mingw

dlltool --dllname postgres.exe --output-exp postgres.exp --def
postgres.def
gcc -O2 -fno-strict-aliasing -Wall -Wmissing-prototypes
-Wmissing-declarations -L../../src/port   -o postgres.exe
-Wl,--base-file,postgres.base postgres.exp access/SUBSYS.o
bootstrap/SUBSYS.o catalog/SUBSYS.o parser/SUBSYS.o commands/SUBSYS.o
executor/SUBSYS.o lib/SUBSYS.o libpq/SUBSYS.o main/SUBSYS.o
nodes/SUBSYS.o optimizer/SUBSYS.o port/SUBSYS.o postmaster/SUBSYS.o
regex/SUBSYS.o rewrite/SUBSYS.o storage/SUBSYS.o tcop/SUBSYS.o
utils/SUBSYS.o ../../src/timezone/SUBSYS.o win32ver.o  -lpgport_srv -lz
-lwsock32 -lcrypt -lm  -lws2_32
access/SUBSYS.o(.text+0x24ba4):xact.c: undefined reference to
`MemoryContextIsEmpty'
access/SUBSYS.o(.text+0x24be9):xact.c: undefined reference to
`XactLockTableDelete'
collect2: ld returned 1 exit status
make[2]: *** [postgres] Error 1
make[2]: Leaving directory `/u/postgresql-snapshot/src/backend'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/u/postgresql-snapshot/src'
make: *** [all] Error 2