audit warnings during snap build

[tartley]

No description provided.

[tartley]

eg. while building ctags:

parsers/html.c: In function ‘readTag.part.2’:
parsers/html.c:584:6: warning: ‘lineOffset_tmp[1]’ may be used uninitialized in this function [-Wmaybe-uninitialized]
      makePromise ("JavaScript", startLineNumber, startLineOffset,
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          endLineNumber, endLineOffset, startSourceLineNumber);
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
parsers/html.c:584:6: warning: ‘line_tmp[1]’ may be used uninitialized in this function [-Wmaybe-uninitialized]

[tartley]

AR libctags.a
ar: u' modifier ignored since D' is the default (see `U')

[masatake]

About the former one, see universal-ctags/ctags#1496