o BSD/OS で、 Seek error となるのを修正 (BSD/OS)
      o $HOME/.jvimrc 等で exrc と fexrc の両方を set していて、カレン
        トディレクトリに .jvimrc や .vimrc があると segmentation fault
        (core dumped) で落ちるのを修正 (ALL)

==============================================================================
*** /tmp/cmdline.c      Tue Mar 28 07:10:28 2000
--- cmdline.c   Fri Apr 07 06:36:26 2000
***************
*** 3591,3597 ****
                return FAIL;
  #endif
  #ifdef FEXRC
!       if (p_fexrc)
        {
                STRCPY(NameBuff, curbuf->b_filename);
                q = NameBuff;
--- 3591,3597 ----
                return FAIL;
  #endif
  #ifdef FEXRC
!       if (p_fexrc && curbuf->b_filename != NULL)
        {
                STRCPY(NameBuff, curbuf->b_filename);
                q = NameBuff;
*** /tmp/memfile.c      Fri Dec 10 02:04:36 1999
--- memfile.c   Mon Apr 03 00:21:34 2000
***************
*** 824,830 ****
        page_size = mfp->mf_page_size;
        offset = page_size * hp->bh_bnum;
        size = page_size * hp->bh_page_count;
! #ifdef __FreeBSD__
        if (lseek(mfp->mf_fd, (off_t)offset, SEEK_SET) != offset)
  #else
        if (lseek(mfp->mf_fd, offset, SEEK_SET) != offset)
--- 824,830 ----
        page_size = mfp->mf_page_size;
        offset = page_size * hp->bh_bnum;
        size = page_size * hp->bh_page_count;
! #if defined(__FreeBSD__) || defined(__bsdi__)
        if (lseek(mfp->mf_fd, (off_t)offset, SEEK_SET) != offset)
  #else
        if (lseek(mfp->mf_fd, offset, SEEK_SET) != offset)
***************
*** 885,891 ****
                        hp2 = hp;

                offset = page_size * nr;
! #ifdef __FreeBSD__
                if (lseek(mfp->mf_fd, (off_t)offset, SEEK_SET) != offset)
  #else
                if (lseek(mfp->mf_fd, offset, SEEK_SET) != offset)
--- 885,891 ----
                        hp2 = hp;

                offset = page_size * nr;
! #if defined(__FreeBSD__) || defined(__bsdi__)
                if (lseek(mfp->mf_fd, (off_t)offset, SEEK_SET) != offset)
  #else
                if (lseek(mfp->mf_fd, offset, SEEK_SET) != offset)