fileops/repository: create (most) directories with 0777 permissions

To further match how Git behaves, this change makes most of the
directories libgit2 creates in a git repo have a file mode of
0777. Specifically:

- Intermediate directories created with git_futils_mkpath2file() have
  0777 permissions. This affects odb_loose, reflog, and refs.

- The top level folder for bare repos is created with 0777
  permissions.

- The top level folder for non-bare repos is created with 0755
  permissions.

- /objects/info/, /objects/pack/, /refs/heads/, and /refs/tags/ are
  created with 0777 permissions.

Additionally, the following changes have been made:

- fileops functions that create intermediate directories have grown a
  new dirmode parameter. The only exception to this is filebuf's
  lock_file(), which unconditionally creates intermediate directories
  with 0777 permissions when GIT_FILEBUF_FORCE is set.

- The test runner now sets the umask to 0 before running any
  tests. This ensurses all file mode checks are consistent across
  systems.

- t09-tree.c now does a directory permissions check. I've avoided
  adding this check to other tests that might reuse existing
  directories from the prefabricated test repos. Because they're
  checked into the repo, they have 0755 permissions.

- Other assorted directories created by tests have 0777 permissions.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/fileops.h b/src/fileops.h
index 176888895..56c4770cb 100644
--- a/src/fileops.h
+++ b/src/fileops.h
@@ -48,7 +48,7 @@ extern int git_futils_exists(const char *path);
  * Create and open a file, while also
  * creating all the folders in its path
  */
-extern int git_futils_creat_withpath(const char *path, const mode_t mode);
+extern int git_futils_creat_withpath(const char *path, const mode_t dirmode, const mode_t mode);
 
 /**
  * Create an open a process-locked file
@@ -59,7 +59,7 @@ extern int git_futils_creat_locked(const char *path, const mode_t mode);
  * Create an open a process-locked file, while
  * also creating all the folders in its path
  */
-extern int git_futils_creat_locked_withpath(const char *path, const mode_t mode);
+extern int git_futils_creat_locked_withpath(const char *path, const mode_t dirmode, const mode_t mode);
 
 /**
  * Check if the given path points to a directory
@@ -80,7 +80,7 @@ extern int git_futils_mkdir_r(const char *path, const mode_t mode);
  * Create all the folders required to contain
  * the full path of a file
  */
-extern int git_futils_mkpath2file(const char *path);
+extern int git_futils_mkpath2file(const char *path, const mode_t mode);
 
 extern int git_futils_rmdir_r(const char *path, int force);
 
@@ -98,7 +98,7 @@ extern int git_futils_mv_atomic(const char *from, const char *to);
  * Move a file on the filesystem, create the
  * destination path if it doesn't exist
  */
-extern int git_futils_mv_withpath(const char *from, const char *to);
+extern int git_futils_mv_withpath(const char *from, const char *to, const mode_t dirmode);
 
 
 /**