Description of problem:
gcc-4.0.0 regression in '\' escape handling in gsub()

gcc-3.1.8 works ok.

Version-Release number of selected component (if applicable):
gawk-4.0.0-1.fc16.x86_64

How reproducible:
100%

Steps to Reproduce:
1. echo '\\' | gawk '{gsub("\\\\","\\\\",$0); print($0);}'
2.
3.
  
Actual results:
\\

Expected results:
\\\\

Additional info:
This breaks the ~20 year old stringize.awk script in graphviz that converts postscript text into C strings.

This problem has also been reported by email to bug-gawk