diff --git a/libgo/go/cmd/go/internal/load/pkg.go b/libgo/go/cmd/go/internal/load/pkg.go
index b2a757a..882b86d 100644
--- a/libgo/go/cmd/go/internal/load/pkg.go
+++ b/libgo/go/cmd/go/internal/load/pkg.go
@@ -1010,7 +1010,7 @@
 
 	// Cgo translation adds imports of "runtime/cgo" and "syscall",
 	// except for certain packages, to avoid circular dependencies.
-	if p.UsesCgo() && (!p.Standard || !cgoExclude[p.ImportPath]) {
+	if p.UsesCgo() && (!p.Standard || !cgoExclude[p.ImportPath]) && cfg.BuildContext.Compiler != "gccgo" {
 		addImport("runtime/cgo")
 	}
 	if p.UsesCgo() && (!p.Standard || !cgoSyscallExclude[p.ImportPath]) {
@@ -1019,7 +1019,9 @@
 
 	// SWIG adds imports of some standard packages.
 	if p.UsesSwig() {
-		addImport("runtime/cgo")
+		if cfg.BuildContext.Compiler != "gccgo" {
+			addImport("runtime/cgo")
+		}
 		addImport("syscall")
 		addImport("sync")
 
@@ -1225,7 +1227,7 @@
 	deps := []string{"runtime"}
 
 	// External linking mode forces an import of runtime/cgo.
-	if externalLinkingForced(p) {
+	if externalLinkingForced(p) && cfg.BuildContext.Compiler != "gccgo" {
 		deps = append(deps, "runtime/cgo")
 	}
 	// On ARM with GOARM=5, it forces an import of math, for soft floating point.
diff --git a/libgo/go/cmd/go/internal/vet/vetflag.go b/libgo/go/cmd/go/internal/vet/vetflag.go
index d4664cc..03770ea 100644
--- a/libgo/go/cmd/go/internal/vet/vetflag.go
+++ b/libgo/go/cmd/go/internal/vet/vetflag.go
@@ -90,7 +90,7 @@
 			}
 			switch f.Name {
 			// Flags known to the build but not to vet, so must be dropped.
-			case "x", "n", "vettool":
+			case "x", "n", "vettool", "compiler":
 				if extraWord {
 					args = append(args[:i], args[i+2:]...)
 					extraWord = false
diff --git a/libgo/go/cmd/go/internal/work/exec.go b/libgo/go/cmd/go/internal/work/exec.go
index 85bdff8..837ffb5 100644
--- a/libgo/go/cmd/go/internal/work/exec.go
+++ b/libgo/go/cmd/go/internal/work/exec.go
@@ -512,6 +512,7 @@
 			ImportPath:  a.Package.ImportPath,
 			ImportMap:   make(map[string]string),
 			PackageFile: make(map[string]string),
+			Standard:    make(map[string]bool),
 		}
 		a.vetCfg = vcfg
 		for i, raw := range a.Package.Internal.RawImports {
@@ -548,17 +549,24 @@
 
 	for _, a1 := range a.Deps {
 		p1 := a1.Package
-		if p1 == nil || p1.ImportPath == "" || a1.built == "" {
+		if p1 == nil || p1.ImportPath == "" {
 			continue
 		}
-		fmt.Fprintf(&icfg, "packagefile %s=%s\n", p1.ImportPath, a1.built)
+		if a1.built != "" {
+			fmt.Fprintf(&icfg, "packagefile %s=%s\n", p1.ImportPath, a1.built)
+		}
 		if vcfg != nil {
 			// Add import mapping if needed
 			// (for imports like "runtime/cgo" that appear only in generated code).
 			if !vcfgMapped[p1.ImportPath] {
 				vcfg.ImportMap[p1.ImportPath] = p1.ImportPath
 			}
-			vcfg.PackageFile[p1.ImportPath] = a1.built
+			if a1.built != "" {
+				vcfg.PackageFile[p1.ImportPath] = a1.built
+			}
+			if p1.Standard {
+				vcfg.Standard[p1.ImportPath] = true
+			}
 		}
 	}
 
@@ -693,6 +701,7 @@
 	GoFiles     []string
 	ImportMap   map[string]string
 	PackageFile map[string]string
+	Standard    map[string]bool
 	ImportPath  string
 
 	SucceedOnTypecheckFailure bool
@@ -722,7 +731,10 @@
 	if vcfg.ImportMap["fmt"] == "" {
 		a1 := a.Deps[1]
 		vcfg.ImportMap["fmt"] = "fmt"
-		vcfg.PackageFile["fmt"] = a1.built
+		if a1.built != "" {
+			vcfg.PackageFile["fmt"] = a1.built
+		}
+		vcfg.Standard["fmt"] = true
 	}
 
 	// During go test, ignore type-checking failures during vet.
diff --git a/libgo/go/cmd/vet/main.go b/libgo/go/cmd/vet/main.go
index 9d28ebd..49c1d32 100644
--- a/libgo/go/cmd/vet/main.go
+++ b/libgo/go/cmd/vet/main.go
@@ -292,6 +292,7 @@
 	GoFiles     []string
 	ImportMap   map[string]string
 	PackageFile map[string]string
+	Standard    map[string]bool
 
 	SucceedOnTypecheckFailure bool
 
@@ -309,7 +310,12 @@
 	if p == "" {
 		return nil, fmt.Errorf("unknown import path %q", path)
 	}
-	if v.PackageFile[p] == "" && v.Compiler != "gccgo" {
+	if v.PackageFile[p] == "" {
+		if v.Compiler == "gccgo" && v.Standard[path] {
+			// gccgo doesn't have sources for standard library packages,
+			// but the importer will do the right thing.
+			return v.imp.Import(path)
+		}
 		return nil, fmt.Errorf("unknown package file for import %q", path)
 	}
 	return v.imp.Import(p)
@@ -318,6 +324,10 @@
 func (v *vetConfig) openPackageFile(path string) (io.ReadCloser, error) {
 	file := v.PackageFile[path]
 	if file == "" {
+		if v.Compiler == "gccgo" && v.Standard[path] {
+			// The importer knows how to handle this.
+			return nil, nil
+		}
 		// Note that path here has been translated via v.ImportMap,
 		// unlike in the error in Import above. We prefer the error in
 		// Import, but it's worth diagnosing this one too, just in case.
diff --git a/libgo/go/go/internal/gccgoimporter/importer.go b/libgo/go/go/internal/gccgoimporter/importer.go
index 843d196..ddaed40 100644
--- a/libgo/go/go/internal/gccgoimporter/importer.go
+++ b/libgo/go/go/internal/gccgoimporter/importer.go
@@ -176,7 +176,7 @@
 				return p, nil
 			}
 			rc, err := lookup(pkgpath)
-			if err == nil {
+			if err == nil && rc != nil {
 				defer rc.Close()
 				rs, ok := rc.(io.ReadSeeker)
 				if !ok {