PDFs no longer created: error: -dCompatibilityLevel=1.4

[ivan . k . kuznetsov]

Lilypond .ly files that created .pdf files just fine
a few weeks ago no longer work.  I get the messages:


   Preprocessing graphical objects...
   Finding the ideal number of pages...
   Fitting music on 1 page...
   Drawing systems...
   Layout output to `song01.ps'...
   Converting to `./song01.pdf'...
   `gs -q -dSAFER -dDEVICEWIDTHPOINTS=612.00 -dDEVICEHEIGHTPOINTS=792.00 
-dCompatibilityLevel=1.4 -dNOPAUSE -dBATCH -r1200 -sDEVICE=pdfwrite 
-sOutputFile="./song01.pdf" -c .setpdfwrite -f "song01.ps"' failed (256)
   error: failed files: "song01.ly"


I am using version \version "2.12.3" and I have _not_ upgraded
my lilypond installation ever ( I have only been using lilypond
less than two months).


My OS is CentOS 5.6 and I have done perhaps 100 or more package
updates to the operating system in the last week though.  Among
other packages that were updated was the Cups package.  Several
libraries were also updated.

Might updating the OS packages have caused lilypond to
no longer produce .pdf files?

If so, I guess a solution would be to uninstall and then
reinstall lilypond?

Thanks;