Fix a C++ link issue: If constant strings used only in constructor, the don't...

Fix a C++ link issue: If constant strings used only in constructor, the don't get linked into the final executable

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4743 42af7a65-404d-4744-a932-0658087f49c3