GCC4 does not compile the latest Samba release because an array is being made
with an incomplete type.

Compiling lib/version.c
Compiling client/smbmnt.c
Compiling lib/snprintf.c
In file included from include/smb.h:1679,
                 from include/includes.h:819,
                 from lib/version.c:22:
include/popt_common.h:25: error: array type has incomplete element type
include/popt_common.h:26: error: array type has incomplete element type
include/popt_common.h:27: error: array type has incomplete element type
include/popt_common.h:28: error: array type has incomplete element type
In file included from include/smb.h:1679,
                 from include/includes.h:819,
                 from client/smbmnt.c:9:
include/popt_common.h:25: error: array type has incomplete element type
include/popt_common.h:26: error: array type has incomplete element type
include/popt_common.h:27: error: array type has incomplete element type
include/popt_common.h:28: error: array type has incomplete element type
make: *** [lib/version.o] Error 1
make: *** Waiting for unfinished jobs....
make: *** [client/smbmnt.o] Error 1 

The simplest solution is to make it a defined type by adding the include. 
Attached is a patch.