In the syntax stuff, the c.vim file should be changed to have the following:
Old:
syn region cString start=+"+ skip=+\\\\\|\\"+ end=+"+
contains=cSpecial
New
syn region cString start=+"+ skip=+\\\\\|\\\"\|'+ end=+"+
contains=cSpecial
syn region cString start=+'+ skip=+\\\\\|\\\'\|"+ end=+'+
contains=cSpecial
This would take care of the "......'....." problem and the '"' problem
where strings run off the end of the line because of the embedded single
quote and double quote.
(Hopefully this goes through as text, Mozilla still has the HTML stuff
at the top of the message.)