bug#12776: Windows build fails with commit r110750

[Andy Moreton]

MinGW gcc 4.7.0
Windows XP SP3

The native Windows build fails to compile with r110750 and later
(r110749 is ok). It seems that there are some missing link dependencies
after this change:

gcc -o oo/i386/temacs.bin      -Wl,-stack,0x00800000 -Wl,-heap,0x00100000 
-Wl,-image-base,0x01000000 -Wl,-subsystem,console -Wl,-entry,__start 
-Wl,-Map,oo/i386/temacs.map oo/i386/firstfile.o oo/i386/emacs.res 
oo/i386/temacs0.a oo/i386/temacs1.a oo/i386/temacs2.a oo/i386/lastfile.a 
../lib/oo/i386/libgnu.a -lwinmm -ladvapi32 -lgdi32 -lcomdlg32 -luser32 -lmpr 
-lshell32 -lwinspool -lole32 -lcomctl32 -lusp10
oo/i386/temacs2.a(sysdep.o):sysdep.c:(.text+0x7f2): undefined reference to 
`_getpgrp'
oo/i386/temacs2.a(sysdep.o):sysdep.c:(.text+0x838): undefined reference to 
`_setpgid'
oo/i386/temacs2.a(sysdep.o):sysdep.c:(.text+0x876): undefined reference to 
`_setpgid'
collect2.exe: error: ld returned 1 exit status
makefile:515: recipe for target 'oo/i386/temacs.exe' failed

Could some please take a look ?

   AndyM