Remove extern "C" barriers to using C++.

Change-Id: Ic046d6aa540738cb46b54531bc59ba3b47b0136d
diff --git a/file_sync_client.cpp b/file_sync_client.cpp
index 4ba730b..730a5e2 100644
--- a/file_sync_client.cpp
+++ b/file_sync_client.cpp
@@ -130,8 +130,6 @@
     return -1;
 }
 
-typedef struct syncsendbuf syncsendbuf;
-
 struct syncsendbuf {
     unsigned id;
     unsigned size;
@@ -557,8 +555,6 @@
     }
 }
 
-typedef struct copyinfo copyinfo;
-
 struct copyinfo
 {
     copyinfo *next;
@@ -804,12 +800,12 @@
 }
 
 
-typedef struct {
+struct sync_ls_build_list_cb_args {
     copyinfo **filelist;
     copyinfo **dirlist;
     const char *rpath;
     const char *lpath;
-} sync_ls_build_list_cb_args;
+};
 
 void
 sync_ls_build_list_cb(unsigned mode, unsigned size, unsigned time,