Add some more const (mostly mars.c and link.c)
Align comments
Merge pull request #2714 from yebblies/moreconst

[DDMD] Add some more const (mostly mars.c)
Const-ify the ddoc code
Merge pull request #2718 from yebblies/ddocconst

[DDMD] Const-ify the ddoc code
Const-ify addComment
Merge pull request #2719 from yebblies/addcommentconst

[DDMD] Const-ify addComment
Fix compile1.bug6720 already defined error
Merge pull request #2720 from ibuclaw/compile1

Fix compile1.bug6720 already defined error