Move C++ check into iostream/Makefile

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@34175 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/iostream/Makefile

@@ -8,4 +8,8 @@ ifneq ($(USE_LARGEFILES),)
 	EXTRA_CFLAGS = -D_FILE_OFFSET_BITS=64
 endif
 
+ifneq ($(strip $(CXX)),)
 default: stlib
+else
+default:
+endif