Clean up some prototypes
fix Issue 13413 - dmd does not follow symlink when searching for dmd.conf

- first search argv0 in PATH then resolve symbolic links
Merge pull request #3941 from MartinNowak/fix13413

fix Issue 13413 - dmd does not follow symlink when searching for dmd.conf
Merge pull request #3936 from yebblies/cleanup2

[cleanup] Clean up some prototypes and dead code
fix Issue 13415 - '-inline' causes wrong enclosing scope pointer for nested function called from templated struct