Data-Dumper: Rmv impediment to compiling under C++11

Data-Dumper: Rmv impediment to compiling under C++11

C++11 changed from earlier versions to require space between the end of
a string literal and a macro, so that a feature can unambiguously be
added to the language.  Starting in g++ 6.2, the compiler emits a
deprecation warning when there isn't a space (presumably so that future
versions can support C++11).

Although not required by the C++11 change, this patch also makes sure
there is space after a macro call, before a string literal.  This makes
the macro stand out, and is easier to read.  As part of this, useless ""
following the macro are removed.

This patch also changes the affected lines to not exceed 79 columns, as
specified by perlhack.

Code and modules included with the Perl core need to be compilable using
C++.  This is so that perl can be embedded in C++ programs. (Actually,
only the hdr files need to be so compilable, but it would be hard to
test that just the hdrs are compilable.)  So we need to accommodate
changes to the C++ language.