Add FUSE_FILL_DIR_DEFAULTS enum (#903)

In order to use the fuse_fill_dir_t function in a C++ program, add the enum item:
FUSE_FILL_DIR_DEFAULTS

Without this change g++ compilation failed with
example/hello.c:94:35: error: invalid conversion from ‘int’ to ‘fuse_fill_dir_flags’ [-fpermissive]
   94 |         filler(buf, ".", NULL, 0, 0);
      |                                   ^
      |                                   |
      |                                   int

6 files changed, 12 insertions, 10 deletions

diff --git a/example/hello.c b/example/hello.c
index b24ebfe..6df8173 100644
--- a/example/hello.c
+++ b/example/hello.c
@@ -91,9 +91,9 @@ static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
 	if (strcmp(path, "/") != 0)
 		return -ENOENT;
 
-	filler(buf, ".", NULL, 0, 0);
-	filler(buf, "..", NULL, 0, 0);
-	filler(buf, options.filename, NULL, 0, 0);
+	filler(buf, ".", NULL, 0, FUSE_FILL_DIR_DEFAULTS);
+	filler(buf, "..", NULL, 0, FUSE_FILL_DIR_DEFAULTS);
+	filler(buf, options.filename, NULL, 0, FUSE_FILL_DIR_DEFAULTS);
 
 	return 0;
 }
diff --git a/example/invalidate_path.c b/example/invalidate_path.c
index 9159b2f..0e8d77f 100644
--- a/example/invalidate_path.c
+++ b/example/invalidate_path.c
@@ -117,9 +117,9 @@ static int xmp_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
 		(void) buf;
 		struct stat file_stat;
 		xmp_getattr("/" TIME_FILE_NAME, &file_stat, NULL);
-		filler(buf, TIME_FILE_NAME, &file_stat, 0, 0);
+		filler(buf, TIME_FILE_NAME, &file_stat, 0, FUSE_FILL_DIR_DEFAULTS);
 		xmp_getattr("/" GROW_FILE_NAME, &file_stat, NULL);
-		filler(buf, GROW_FILE_NAME, &file_stat, 0, 0);
+		filler(buf, GROW_FILE_NAME, &file_stat, 0, FUSE_FILL_DIR_DEFAULTS);
 		return 0;
 	}
 }
diff --git a/example/ioctl.c b/example/ioctl.c
index b8dab00..9fe5c5b 100644
--- a/example/ioctl.c
+++ b/example/ioctl.c
@@ -181,9 +181,9 @@ static int fioc_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
 	if (fioc_file_type(path) != FIOC_ROOT)
 		return -ENOENT;
 
-	filler(buf, ".", NULL, 0, 0);
-	filler(buf, "..", NULL, 0, 0);
-	filler(buf, FIOC_NAME, NULL, 0, 0);
+	filler(buf, ".", NULL, 0, FUSE_FILL_DIR_DEFAULTS);
+	filler(buf, "..", NULL, 0, FUSE_FILL_DIR_DEFAULTS);
+	filler(buf, FIOC_NAME, NULL, 0, FUSE_FILL_DIR_DEFAULTS);
 
 	return 0;
 }
diff --git a/example/passthrough_fh.c b/example/passthrough_fh.c
index 701d59e..3602c96 100644
--- a/example/passthrough_fh.c
+++ b/example/passthrough_fh.c
@@ -167,7 +167,7 @@ static int xmp_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
 	while (1) {
 		struct stat st;
 		off_t nextoff;
-		enum fuse_fill_dir_flags fill_flags = 0;
+		enum fuse_fill_dir_flags fill_flags = FUSE_FILL_DIR_DEFAULTS;
 
 		if (!d->entry) {
 			d->entry = readdir(d->dp);
diff --git a/example/poll.c b/example/poll.c
index fd53ec0..ffcb4f1 100644
--- a/example/poll.c
+++ b/example/poll.c
@@ -114,7 +114,7 @@ static int fsel_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
 
 	for (i = 0; i < FSEL_FILES; i++) {
 		name[0] = fsel_hex_map[i];
-		filler(buf, name, NULL, 0, 0);
+		filler(buf, name, NULL, 0, FUSE_FILL_DIR_DEFAULTS);
 	}
 
 	return 0;
diff --git a/include/fuse.h b/include/fuse.h
index f0c6f10..90ee4bb 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -48,6 +48,7 @@ enum fuse_readdir_flags {
 	 * FUSE_FILL_DIR_FLAGS for the filler function.  The filesystem may also
 	 * just ignore this flag completely.
 	 */
+	FUSE_READDIR_DEFAULTS = 0,
 	FUSE_READDIR_PLUS = (1 << 0)
 };
 
@@ -64,6 +65,7 @@ enum fuse_fill_dir_flags {
 	 * It is okay to set FUSE_FILL_DIR_PLUS if FUSE_READDIR_PLUS is not set
 	 * and vice versa.
 	 */
+	FUSE_FILL_DIR_DEFAULTS = 0,
 	FUSE_FILL_DIR_PLUS = (1 << 1)
 };