mt-ospace (CFLAGS_FOR_TARGET): Append -g -Os rather than overwriting.

2014-11-17  Bob Dunlop  <bob.dunlop@xyzzy.org.uk>

        * mt-ospace (CFLAGS_FOR_TARGET): Append -g -Os rather than
        overwriting.
        (CXXFLAGS_FOR_TARGET): Similarly.

From-SVN: r217739

config/ChangeLog

+2014-11-17  Bob Dunlop  <bob.dunlop@xyzzy.org.uk>
+
+	* mt-ospace (CFLAGS_FOR_TARGET): Append -g -Os rather than
+	overwriting.
+	(CXXFLAGS_FOR_TARGET): Similarly.
+
 2014-11-17  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR bootstrap/63888

config/mt-ospace

 # Build libraries optimizing for space, not speed.
- CFLAGS_FOR_TARGET = -g -Os
- CXXFLAGS_FOR_TARGET = -g -Os
+ CFLAGS_FOR_TARGET += -g -Os
+ CXXFLAGS_FOR_TARGET += -g -Os