$ perl -V:ldflags
ldflags='-s -L"c:\perl\5.14.1\lib\MSWin32-x86-multi-thread\CORE" -L"C:\MinGW\lib"';

$ perl -V:archlib
archlib='c:\perl\5.14.1\lib\MSWin32-x86-multi-thread';

$ grep -ri "define off_t " C:\perl\5.14.1\lib\MSWin32-x86-multi-thread\CORE
C:\perl\5.14.1\lib\MSWin32-x86-multi-thread\CORE/config.h:#define Off_t long long               /* <offset> type */
C:\perl\5.14.1\lib\MSWin32-x86-multi-thread\CORE/perl.h:#       define Off_t off64_t
C:\perl\5.14.1\lib\MSWin32-x86-multi-thread\CORE/uconfig.h:#define Off_t int            /* <offset> type */