Add prototype for handlefile, so that it is possible to call it before it

is defined.  Future compilers are likely not to accept implicit function

declarations by default.

Submitted upstream: <https://sourceforge.net/p/xbiso/patches/3/>

diff --git a/xbiso.c b/xbiso.c

index 6372944f7ec91120..c472c040d96e48a9 100644

--- a/xbiso.c

+++ b/xbiso.c

@@ -93,6 +93,7 @@ typedef off_t OFFT;

 typedef off64_t OFFT;

 #endif

+int handlefile(OFFT offset, int dtable);

 int main(int argc, char *argv[]) {

   char *dbuf,*fname;

@@ -269,6 +270,7 @@ int main(int argc, char *argv[]) {

   exit(0);

 }

+int

 handlefile(OFFT offset, int dtable) {

   TABLE dirent;