Add -fno-strict-aliasing workaround for all GCC targets

Use a GCC option to work around aliasing bugs. See commit 013dbcd for
more details.
diff --git a/configs/sunos5-gcc b/configs/sunos5-gcc
index 77b293c..c5e443f 100644
--- a/configs/sunos5-gcc
+++ b/configs/sunos5-gcc
@@ -28,6 +28,10 @@
 
 GLUT_CFLAGS = -fexceptions -DSOLARIS_2_4_BUG
 
+# Work around aliasing bugs - developers should comment this out
+CFLAGS += -fno-strict-aliasing
+CXXFLAGS += -fno-strict-aliasing
+
 # Library/program dependencies
 EXTRA_LIB_PATH=-L/usr/openwin/lib