What steps will reproduce the problem?
1. File containing: PAT and ä (0xE4, a umlaut), ö (0xF6,o umlaut), other high 
bit ascii chars
2. cindex -reset .
3. csearch -i PAT

What is the expected output? What do you see instead?
Expected to find PAT. Instead no match.

What version of the product are you using? On what operating system?
codesearch-0.01-windows-amd64.zip

Please provide any additional information below.
I looked at the source (write.go) and it seems to expect that files are in 
UTF-8 only (this is a Go specification?). However it would be nice if csearch 
could be used with any source files, including those with high bit ascii 
characters. Or that there would be a command line option for this.