Log Message:
Changes 10.35.76:
* Pnmtopng:  -libversion doesn't report level of linked libz.
  It was a modularity violation and caused build failures on
  Mac OS X, because Pnmtopng per se doesn't know about libz --
  it's used by libpng.
* Build: don't fail due to SIGRTMIN, SIGRTMAX being undefined.

Changes 10.35.75:
* palmtopnm: fix for pixel size 16.
* pamscale: fix -reduce.  Introduced in 10.27.
* configure: default to 'none' for Svgalib if it doesn't appear to
  be installed (per 'ldconfig').  Ported from 10.38, released March 2007.

Changes 10.35.74:
* pbmtext: don't crash when font file contains a blank line.
  Fail cleanly.
* ppmtoilbm: fix arithmetic overflow with image dimension
  represented as 16 bit integer.
* pbmpage: fix garbage output.
* pnmhistmap: Fix crash with -width.  Always broken.
* Build: don't fail due to SIGPWR being undefined.