libstdc++: Pass CXXFLAGS to check_performance script

It looks like our check-performance target runs completely unoptimized,
which is a bit silly. This exports the CXXFLAGS from the parent make
process to the check_performance script.

libstdc++-v3/ChangeLog:

	* scripts/check_performance: Use gnu++11 instead of gnu++0x.
	* testsuite/Makefile.am (check-performance): Export CXXFLAGS to
	child process.
	* testsuite/Makefile.in: Regenerate.

libstdc++-v3/scripts/check_performance

@@ -32,7 +32,7 @@ SH_FLAG="-Wl,--rpath -Wl,$BUILD_DIR/../../gcc \
          -Wl,--rpath -Wl,$BUILD_DIR/src/.libs"
 ST_FLAG="-static"
 LINK=$SH_FLAG
-CXX="$COMPILER $INCLUDES $FLAGS -std=gnu++0x $CXXFLAGS $LINK"
+CXX="$COMPILER $INCLUDES $FLAGS -std=gnu++11 $CXXFLAGS $LINK"
 LIBS="./libtestc++.a"
 TESTS_FILE="testsuite_files_performance"
 

libstdc++-v3/testsuite/Makefile.am

@@ -182,6 +182,7 @@ check-compile: testsuite_files ${compile_script}
 check_performance_script=${glibcxx_srcdir}/scripts/check_performance
 check-performance: testsuite_files_performance ${performance_script}
 	-@(chmod + ${check_performance_script}; \
+	  export CXXFLAGS="$(CXXFLAGS)"; \
 	  ${check_performance_script} ${glibcxx_srcdir} ${glibcxx_builddir})
 
 # Runs the testsuite in debug mode.

libstdc++-v3/testsuite/Makefile.in

@@ -703,6 +703,7 @@ check-compile: testsuite_files ${compile_script}
 	  ${compile_script} ${glibcxx_srcdir} ${glibcxx_builddir})
 check-performance: testsuite_files_performance ${performance_script}
 	-@(chmod + ${check_performance_script}; \
+	  export CXXFLAGS="$(CXXFLAGS)"; \
 	  ${check_performance_script} ${glibcxx_srcdir} ${glibcxx_builddir})
 
 check-debug: site.exp