Dumb work-around for GNU indent extern C bug

bug #65165: extern "C" mishandled in header files
https://savannah.gnu.org/bugs/index.php?65165

--- a/src/ext4_sb.h
+++ b/src/ext4_sb.h
@@ -21,9 +21,11 @@
 
 #define EXT4_SUPER_MAGIC 0xEF53
 
+/*
 #ifdef __cplusplus
 extern "C" {
 #endif
+*/
 
 struct fs_info {
 	int64_t len;		/* If set to 0, ask the block device for the size,
@@ -47,8 +49,10 @@ struct fs_info {
 
 int ext4_parse_sb(struct ext4_super_block *sb, struct fs_info *info);
 
+/*
 #ifdef __cplusplus
 }
 #endif
+*/
 
 #endif
--- a/src/ext4_utils.h
+++ b/src/ext4_utils.h
@@ -17,9 +17,11 @@
 #ifndef _EXT4_UTILS_H_
 #define _EXT4_UTILS_H_
 
+/*
 #ifdef __cplusplus
 extern "C" {
 #endif
+*/
 
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
@@ -197,8 +199,10 @@ int make_ext4fs_internal(struct fs_info *info, struct fs_aux_info *aux_info,
 int read_ext(struct fs_info *info, struct fs_aux_info *aux_info, int force,
 	     jmp_buf *setjmp_env, int fd, int verbose);
 
+/*
 #ifdef __cplusplus
 }
 #endif
+*/
 
 #endif
--- a/src/libsparse/include/sparse/sparse.h
+++ b/src/libsparse/include/sparse/sparse.h
@@ -21,9 +21,11 @@
 #include <stddef.h>
 #include <stdint.h>
 
+/*
 #ifdef	__cplusplus
 extern "C" {
 #endif
+*/
 
 struct sparse_file;
 
@@ -291,8 +293,10 @@ void sparse_file_verbose(struct sparse_file *s);
  */
 extern void (*sparse_print_verbose)(const char *fmt, ...);
 
+/*
 #ifdef	__cplusplus
 }
 #endif
+*/
 
 #endif
--- a/src/sha1.h
+++ b/src/sha1.h
@@ -21,17 +21,21 @@ typedef struct {
 	u_char buffer[64];
 } SHA1_CTX;
 
+/*
 #ifdef __cplusplus
 extern "C" {
 #endif
+*/
 
 void SHA1Transform(uint32_t[5], const u_char[64]);
 void SHA1Init(SHA1_CTX *);
 void SHA1Update(SHA1_CTX *, const u_char *, u_int);
 void SHA1Final(u_char[SHA1_DIGEST_LENGTH], SHA1_CTX *);
 
+/*
 #ifdef __cplusplus
 }
 #endif
+*/
 
 #endif /* _SYS_SHA1_H_ */