-# During gcc bootstrap, if we use some random cc for stage1 then
-# CFLAGS will be just -g. We want to ensure that TARGET libraries
-# (which we know are built with gcc) are built with optimizations so
-# prepend -O2 when setting CFLAGS_FOR_TARGET.
-CFLAGS_FOR_TARGET = -O2 $(CFLAGS) $(SYSROOT_CFLAGS_FOR_TARGET) \
+# During gcc bootstrap, if we use some random cc for stage1 then CFLAGS
+# might be empty or "-g". We don't require a C++ compiler, so CXXFLAGS
+# might also be empty (or "-g", if a non-GCC C++ compiler is in the path).
+# We want to ensure that TARGET libraries (which we know are built with
+# gcc) are built with "-O2 -g", so prepend those options when setting
+# CFLAGS_FOR_TARGET and CXXFLAGS_FOR_TARGET.
+CFLAGS_FOR_TARGET = -O2 -g $(CFLAGS) $(SYSROOT_CFLAGS_FOR_TARGET) \