cmStandardIncludes: Add new cmHasLiteralPrefix function.

This allows avoiding error-prone hard-coding of literal
string lengths.

Borland is not able to process the template version of this
method. Make it use the macro version instead. This means
that Borland will also use the macro versions of cmArray*.
Use new cmHasLiteralPrefix function
Merge topic 'add-cmLiteralNCompare' into next

73dee66 Use new cmHasLiteralPrefix function
033c33e cmStandardIncludes: Add new cmHasLiteralPrefix function.