cmd/compile/internal/gc: cleaning lex.go

Cleaning along the way:
-convert variable types from int to bool
-remove unnecessary functions
-remove unnecessary type conversion
-remove unnecessary variable declarations
-transform struct{string,string} with lookup to map[string]string

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I259728fe4afd7f23b67f08fab856ce0abee57b21
Reviewed-on: https://go-review.googlesource.com/14435
Reviewed-by: Ian Lance Taylor <[email protected]>

src/cmd/compile/internal/gc/go.go

@@ -382,12 +382,12 @@ type Sig struct {
 type Io struct {
 	infile     string
 	bin        *obj.Biobuf
-	nlsemi     int
-	eofnl      int
+	cp         string // used for content when bin==nil
 	last       int
 	peekc      int
-	peekc1     int    // second peekc for ...
-	cp         string // used for content when bin==nil
+	peekc1     int // second peekc for ...
+	nlsemi     bool
+	eofnl      bool
 	importsafe bool
 }
 
@@ -598,7 +598,7 @@ var incannedimport int
 
 var statuniqgen int // name generator for static temps
 
-var loophack int
+var loophack bool
 
 var iota_ int32
 

src/cmd/compile/internal/gc/go.y

@@ -2311,6 +2311,6 @@ func fixlbrace(lbr int) {
 	// set up for another one now that we're done.
 	// See comment in lex.C about loophack.
 	if lbr == LBODY {
-		loophack = 1
+		loophack = true
 	}
 }