[Bug-gnubg] Linking errors due to recent changes

[Philippe Michel]

On freebsd 7.0, some of the recent "Small changes for visual studio 2008" 
cause linking errors :

bearoff.o(.text+0x168): In function `ReadBearoffFile':
/home/pm/src/gnubg/bearoff.c:291: undefined reference to `_lseek'
bearoff.o(.text+0x1486): In function `BearoffInit':
/home/pm/src/gnubg/bearoff.c:866: undefined reference to `_lseek'
util.o(.text+0x61): In function `GetTemporaryFile':
/home/pm/src/gnubg/util.c:105: undefined reference to `_fdopen'