Log Message:
Changes 10.35.80:
* asciitopgm: fix bug: memory corruption on too-long lines.
* asciitopgm: fix bug: improper handling of blank lines.

Changes 10.35.79:
* configure: don't default to /usr/X11R6/lib/libX11.so just because
  /usr/X11R6 exists.  /usr/X11R6/lib must exist.
* pngtopnm: fix bug: -verbose reports history chunk present when
  it's really a palette.