Merge branch 'work/pt/for-junio' of git://repo.or.cz/git/mingw/4msysgit

* 'work/pt/for-junio' of git://repo.or.cz/git/mingw/4msysgit:
  Add MinGW-specific execv() override.
  Fix Windows-specific macro redefinition warning.
  Fix 'clone' failure at DOS root directory.
  mingw: do not crash on open(NULL, ...)
  git-am: fix detection of absolute paths for windows
  Side-step MSYS-specific path "corruption" leading to t5560 failure.
  Side-step sed line-ending "corruption" leading to t6038 failure.
  Skip 'git archive --remote' test on msysGit
  Do not strip CR when grepping HTTP headers.
  Skip t1300.70 and 71 on msysGit.
  merge-octopus: Work around environment issue on Windows
  MinGW: Report errors when failing to launch the html browser.
  MinGW: fix stat() and lstat() implementations for handling symlinks
  MinGW: Add missing file mode bit defines
  MinGW: Use pid_t more consequently, introduce uid_t for greater compatibility