Issue on debuild

sblib.cpp: In member function ‘virtual void sb::run()’:
sblib.cpp:1806:9: error: ‘libmnt_context’ was not declared in this scope
         libmnt_context *mcxt(mnt_new_context());
         ^~~~~~~~~~~~~~
sblib.cpp:1806:9: note: suggested alternative: ‘QOpenGLContext’
         libmnt_context *mcxt(mnt_new_context());
         ^~~~~~~~~~~~~~
         QOpenGLContext
sblib.cpp:1806:30: error: ‘mnt_new_context’ was not declared in this scope
         libmnt_context *mcxt(mnt_new_context());
                              ^~~~~~~~~~~~~~~
sblib.cpp:1806:25: error: ‘mcxt’ was not declared in this scope
         libmnt_context *mcxt(mnt_new_context());
                         ^~~~
sblib.cpp:1806:25: note: suggested alternative: ‘acct’
         libmnt_context *mcxt(mnt_new_context());
                         ^~~~
                         acct
sblib.cpp:1807:9: error: ‘mnt_context_set_source’ was not declared in this scope
         mnt_context_set_source(mcxt, bstr(ThrdStr[0])),
         ^~~~~~~~~~~~~~~~~~~~~~
sblib.cpp:1808:9: error: ‘mnt_context_set_target’ was not declared in this scope
         mnt_context_set_target(mcxt, bstr(ThrdStr[1])),
         ^~~~~~~~~~~~~~~~~~~~~~
sblib.cpp:1809:9: error: ‘mnt_context_set_options’ was not declared in this scope
         mnt_context_set_options(mcxt, ! ThrdStr[2].isEmpty() ? bstr(ThrdStr[2]).data : isdir(ThrdStr[0]) ? "bind" : "noatime"),
         ^~~~~~~~~~~~~~~~~~~~~~~
sblib.cpp:1810:22: error: ‘mnt_context_mount’ was not declared in this scope
         ThrdRslt = ! mnt_context_mount(mcxt);
                      ^~~~~~~~~~~~~~~~~
sblib.cpp:1811:16: error: ‘mnt_free_context’ was not declared in this scope
         return mnt_free_context(mcxt);
                ^~~~~~~~~~~~~~~~
sblib.cpp:1811:37: error: return-statement with a value, in function returning 'void' [-fpermissive]
         return mnt_free_context(mcxt);
                                     ^
sblib.cpp: In member function ‘bool sb::umnt(cbstr&)’:
sblib.cpp:2072:5: error: ‘libmnt_context’ was not declared in this scope
     libmnt_context *ucxt(mnt_new_context());
     ^~~~~~~~~~~~~~
sblib.cpp:2072:5: note: suggested alternative: ‘QOpenGLContext’
     libmnt_context *ucxt(mnt_new_context());
     ^~~~~~~~~~~~~~
     QOpenGLContext
sblib.cpp:2072:26: error: ‘mnt_new_context’ was not declared in this scope
     libmnt_context *ucxt(mnt_new_context());
                          ^~~~~~~~~~~~~~~
sblib.cpp:2072:21: error: ‘ucxt’ was not declared in this scope
     libmnt_context *ucxt(mnt_new_context());
                     ^~~~
sblib.cpp:2072:21: note: suggested alternative: ‘umnt’
     libmnt_context *ucxt(mnt_new_context());
                     ^~~~
                     umnt
sblib.cpp:2073:5: error: ‘mnt_context_set_target’ was not declared in this scope
     mnt_context_set_target(ucxt, dev),
     ^~~~~~~~~~~~~~~~~~~~~~
sblib.cpp:2074:5: error: ‘mnt_context_enable_force’ was not declared in this scope
     mnt_context_enable_force(ucxt, true),
     ^~~~~~~~~~~~~~~~~~~~~~~~
sblib.cpp:2075:5: error: ‘mnt_context_enable_lazy’ was not declared in this scope
     mnt_context_enable_lazy(ucxt, true);
     ^~~~~~~~~~~~~~~~~~~~~~~
sblib.cpp:2077:5: error: ‘mnt_context_enable_loopdel’ was not declared in this scope
     mnt_context_enable_loopdel(ucxt, true);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~
sblib.cpp:2079:15: error: ‘mnt_context_umount’ was not declared in this scope
     bool rv(! mnt_context_umount(ucxt));
               ^~~~~~~~~~~~~~~~~~
sblib.cpp:2080:5: error: ‘mnt_free_context’ was not declared in this scope
     mnt_free_context(ucxt);
     ^~~~~~~~~~~~~~~~
sblib.cpp: In lambda function:
sblib.cpp:70:17: warning: this statement may fall through [-Wimplicit-fallthrough=]
                 if(ok) return Nodbg;
                 ^~
sblib.cpp:71:13: note: here
             default:
             ^~~~~~~
sblib.cpp: In member function ‘bool sb::recrmdir(cbstr&, bool)’:
sblib.cpp:1744:25: warning: this statement may fall through [-Wimplicit-fallthrough=]
                         if(slimit && size(fpath) > 8000000) continue;
                         ^~
sblib.cpp:1745:21: note: here
                     default:
                     ^~~~~~~
sblib.cpp:1759:21: warning: this statement may fall through [-Wimplicit-fallthrough=]
                     if(slimit && size(fpath) > 8000000) break;
                     ^~
sblib.cpp:1760:17: note: here
                 default:
                 ^~~~~~~
sblib.cpp: In member function ‘bool sb::thrdsrestore(uchar, cQStr&, cQStr&, cQStr&, bool)’:
sblib.cpp:2630:71: warning: this statement may fall through [-Wimplicit-fallthrough=]
                             if(exist(srci) && lcomp(srci, trgi)) break;
                                                                       ^
sblib.cpp:2632:25: note: here
                         case Isfile:
                         ^~~~
sblib.cpp:2744:41: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                         if(lcomp(srci, trgi)) goto nitem_1;
                                         ^~
sblib.cpp:2745:37: note: here
                                     case Isfile:
                                     ^~~~
sblib.cpp:2992:37: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                     if(! inc && fsize(trgi) > 8000000) break;
                                     ^~
sblib.cpp:2993:33: note: here
                                 case Islink:
                                 ^~~~
sblib.cpp:3022:37: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                     if(lcomp(srci, trgi)) goto nitem_2;
                                     ^~
sblib.cpp:3023:33: note: here
                                 case Isfile:
                                 ^~~~
sblib.cpp:3051:53: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                                     if(! inc && fsize(strgi) > 8000000) break;
                                                     ^~
sblib.cpp:3052:49: note: here
                                                 case Islink:
                                                 ^~~~
sblib.cpp:3081:37: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                     if(skppd) goto nitem_2;
                                     ^~
sblib.cpp:3082:33: note: here
                                 case Islink:
                                 ^~~~
sblib.cpp: In member function ‘bool sb::thrdscopy(uchar, cQStr&, cQStr&)’:
sblib.cpp:3290:41: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                         if(! lcomp(srci, trgi)) goto nitem_1;
                                         ^~
sblib.cpp:3291:37: note: here
                                     case Isfile:
                                     ^~~~
sblib.cpp:3334:45: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                             if(skppd) goto nitem_1;
                                             ^~
sblib.cpp:3336:37: note: here
                                     case Islink:
                                     ^~~~
sblib.cpp:3426:68: warning: this statement may fall through [-Wimplicit-fallthrough=]
                         if(islink(srci) && lcomp(srci, trgi)) break;
                                                                    ^
sblib.cpp:3428:21: note: here
                     case Isfile:
                     ^~~~
sblib.cpp:3559:41: warning: this statement may fall through [-Wimplicit-fallthrough=]
                                         if(lcomp(srci, trgi)) goto nitem_2;
                                         ^~
sblib.cpp:3560:37: note: here
                                     case Isfile:
                                     ^~~~
Makefile:384: set di istruzioni per l'obiettivo "sblib.o" non riuscito
make[2]: *** [sblib.o] Errore 1
make[2]: uscita dalla directory "/root/Scaricati/systemback_1.8.402/libsystemback"
Makefile:49: set di istruzioni per l'obiettivo "sub-libsystemback-make_first" non riuscito
make[1]: *** [sub-libsystemback-make_first] Errore 2
make[1]: uscita dalla directory "/root/Scaricati/systemback_1.8.402"
debian/rules:16: set di istruzioni per l'obiettivo "build-arch-stamp" non riuscito
make: *** [build-arch-stamp] Errore 2
dpkg-buildpackage: Errore: debian/rules build gave error exit status 2
debuild: fatal error at line 1124:
dpkg-buildpackage -rfakeroot -us -uc failed

That's it :(
I cannot resolve by myself, actually, this issue (not declared into scope) and there isn't any systemback older version with sources to try it !
many thanks eanyway for your support ..
replicating errors or solut