Have CanonicalizePath handle \ on Windows

Have CanonicalizePath handle \ on Windows. It's slightly slower to do so, so compensate for that by improving ReadFile to not use text mode (which is a bit slower), and then fixing the lexer to accept \r (it was previously relying on reading files in text mode to remove '\r's).

Timings:

before patch:
qpc: 1229494us
qpc: 1232420us
qpc: 1232493us
qpc: 1235035us
qpc: 1239521us
qpc: 1247100us
avg = 1234867us

with canon of \, fixing parser to accept \r and speedier ReadFile
qpc: 1196304us
qpc: 1200643us
qpc: 1187478us
qpc: 1190062us
qpc: 1182991us
qpc: 1203037us
avg = 1190128us

On Wed Oct 29 2014 at 9:13:52 PM Nico Weber <notifications@github.com>
wrote:

> In src/lexer.in.cc:
>
> > @@ -168,13 +167,15 @@ bool Lexer::PeekToken(Token token) {
> >
> >  void Lexer::EatWhitespace() {
> >    const char* p = ofs_;
> > +  const char* q;
>
> Do you use this for anything?
>
re2c requires it, but only sometimes based on how the DFA is generated.

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> Reply to this email directly or view it on GitHub
> <https://github.com/martine/ninja/pull/839/files#r19587200>.
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