btrfs-progs: kerncompat: hide definition of __init

As kerncompat.h is included from all libbtrfs headers we must be careful
about generic names like __init, in this case it breaks build of
snapper.

Signed-off-by: David Sterba <dsterba@suse.com>

kerncompat.h

@@ -568,7 +568,11 @@ struct work_struct {
 typedef struct wait_queue_head_s {
 } wait_queue_head_t;
 
+/*
+ * __init cannot be defined in kerncompat.h as it's still part of libbtrfs and
+ * the macro name is too generic and can break build.
 #define __init
+*/
 #define __cold
 
 #endif

kernel-shared/compression.h

@@ -78,7 +78,7 @@ static inline unsigned int btrfs_compress_level(unsigned int type_level)
 	return ((type_level & 0xF0) >> 4);
 }
 
-int __init btrfs_init_compress(void);
+int btrfs_init_compress(void);
 void __cold btrfs_exit_compress(void);
 
 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,