api: add go1.1.txt; update cmd/api to use it

R=golang-dev, adg, r
CC=golang-dev
https://golang.org/cl/9250043

src/cmd/api/goapi.go

@@ -38,9 +38,7 @@ import (
 
 // Flags
 var (
-	// TODO(bradfitz): once Go 1.1 comes out, allow the -c flag to take a comma-separated
-	// list of files, rather than just one.
-	checkFile  = flag.String("c", "", "optional filename to check API against")
+	checkFile  = flag.String("c", "", "optional comma-separated filename(s) to check API against")
 	allowNew   = flag.Bool("allow_new", true, "allow API additions")
 	exceptFile = flag.String("except", "", "optional filename of packages that are allowed to change without triggering a failure in the tool")
 	nextFile   = flag.String("next", "", "optional filename of tentative upcoming API features for the next release. This file can be lazily maintained. It only affects the delta warnings from the -c file printed on success.")
@@ -186,7 +184,10 @@ func main() {
 		return
 	}
 
-	required := fileFeatures(*checkFile)
+	var required []string
+	for _, file := range strings.Split(*checkFile, ",") {
+		required = append(required, fileFeatures(file)...)
+	}
 	optional := fileFeatures(*nextFile)
 	exception := fileFeatures(*exceptFile)
 	fail = !compareAPI(bw, features, required, optional, exception)

src/run.bash

@@ -150,7 +150,7 @@ time go run run.go
 
 echo
 echo '# Checking API compatibility.'
-go tool api -c $GOROOT/api/go1.txt -next $GOROOT/api/next.txt -except $GOROOT/api/except.txt
+go tool api -c $GOROOT/api/go1.txt,$GOROOT/api/go1.1.txt -next $GOROOT/api/next.txt -except $GOROOT/api/except.txt
 
 echo
 echo ALL TESTS PASSED

src/run.bat

@@ -121,7 +121,7 @@ set GOMAXPROCS=%OLDGOMAXPROCS%
 set OLDGOMAXPROCS=
 
 echo # Checking API compatibility.
-go tool api -c ..\api\go1.txt -next ..\api\next.txt -except ..\api\except.txt
+go tool api -c ..\api\go1.txt,..\api\go1.1.txt -next ..\api\next.txt -except ..\api\except.txt
 if errorlevel 1 goto fail
 echo.