libstdc++: Improve comments for check_effective_target_cxx11-abi

libstdc++-v3/ChangeLog:

	* testsuite/lib/libstdc++.exp (check_effective_target_cxx11-abi):
	Add comments about which test flags get used by the check.

diff --git a/libstdc++-v3/testsuite/lib/libstdc++.exp b/libstdc++-v3/testsuite/lib/libstdc++.exp
index 78484f7c9afe799afbcc97c92a9190f97e3bf131..fc1e8f242fd13e4b0e123d50e6e88705b13731f5 100644 (file)
--- a/libstdc++-v3/testsuite/lib/libstdc++.exp
+++ b/libstdc++-v3/testsuite/lib/libstdc++.exp
@@ -1524,6 +1524,8 @@ proc check_v3_target_filesystem_ts { } {
 }
 
 # Return 1 if the "cxx11" ABI is in use using the current flags, 0 otherwise.
+# Any flags provided by RUNTESTFLAGS or a target board will be used here.
+# Flags added in the test by dg-options or dg-add-options will not be used.
 proc check_effective_target_cxx11-abi { } {
     global cxxflags