diff --git a/libgo/match.sh b/libgo/match.sh
index c8fb960..281acf7 100755
--- a/libgo/match.sh
+++ b/libgo/match.sh
@@ -135,7 +135,7 @@
 
     if test x$tag1 != xnonmatchingtag -a x$tag2 != xnonmatchingtag; then
 	# Pipe through cat so that `set -e` doesn't affect fgrep.
-	tags=`sed '/^package /q' < $f | grep '^// \?+build ' | cat`
+	tags=`sed '/^package /q' < $f | grep '^// *+build ' | cat`
 	omatch=true
 	first=true
 	match=false
diff --git a/libgo/testsuite/gotest b/libgo/testsuite/gotest
index 9d46916..4f1a2f8 100755
--- a/libgo/testsuite/gotest
+++ b/libgo/testsuite/gotest
@@ -326,7 +326,7 @@
 	    esac
 
 	    if test x$tag1 != xnonmatchingtag -a x$tag2 != xnonmatchingtag; then
-		tags=`sed '/^package /q' < $f | grep '^// \?+build '`
+		tags=`sed '/^package /q' < $f | grep '^// *+build '`
 		omatch=true
 		first=true
 		match=false