Converting some errors into warnings.

src/base/abci/abc.c

@@ -19532,7 +19532,7 @@ int Abc_CommandSeqSweep( Abc_Frame_t * pAbc, int argc, char ** argv )
 
     if ( Abc_NtkIsComb(pNtk) )
     {
-        Abc_Print( -1, "The network is combinational (run \"fraig\" or \"fraig_sweep\").\n" );
+        Abc_Print( 0, "The network is combinational (run \"fraig\" or \"fraig_sweep\").\n" );
         return 0;
     }
 
@@ -31954,7 +31954,7 @@ int Abc_CommandAbc9Scorr( Abc_Frame_t * pAbc, int argc, char ** argv )
     }
     if ( Gia_ManRegNum(pAbc->pGia) == 0 )
     {
-        Abc_Print( -1, "The network is combinational.\n" );
+        Abc_Print( 0, "The network is combinational.\n" );
         return 0;
     }
     pTemp = Cec_ManLSCorrespondence( pAbc->pGia, pPars );

src/base/abci/abcMfs.c

@@ -259,7 +259,7 @@ int Abc_NtkPerformMfs( Abc_Ntk_t * pNtk, Sfm_Par_t * pPars )
     if ( nFaninMax > 6 )
     {
         Abc_Print( 1, "Currently \"mfs\" cannot process the network containing nodes with more than 6 fanins.\n" );
-        return 0;
+        return 1;
     }
     if ( !Abc_NtkHasSop(pNtk) )
         if ( !Abc_NtkToSop( pNtk, -1, ABC_INFINITY ) )