Fix a few more minor memory leaks.

This patch fixes a few more memory leaks that can happen under
error conditions.

vpi/sys_readmem.c

@@ -293,7 +293,10 @@ static PLI_INT32 sys_readmem_calltf(PLI_BYTE8*name)
 
       if (process_params(mitem, start_item, stop_item, callh, name,
                          &start_addr, &stop_addr, &addr_incr,
-                         &min_addr, &max_addr)) return 0;
+                         &min_addr, &max_addr)) {
+	    free(fname);
+	    return 0;
+      }
 
 	/* Open the data file. */
       file = fopen(fname, "r");
@@ -528,7 +531,10 @@ static PLI_INT32 sys_writemem_calltf(PLI_BYTE8*name)
 
       if (process_params(mitem, start_item, stop_item, callh, name,
                          &start_addr, &stop_addr, &addr_incr,
-                         &min_addr, &max_addr)) return 0;
+                         &min_addr, &max_addr)) {
+	    free(fname);
+	    return 0;
+      }
 
       /* Open the data file. */
       file = fopen(fname, "w");

vpi/sys_scanf.c

@@ -626,6 +626,7 @@ static PLI_INT32 sys_fscanf_compiletf(PLI_BYTE8*name)
 	               (int)vpi_get(vpiLineNo, callh));
 	    vpi_printf("%s's first argument (fd) must be numeric.\n", name);
 	    vpi_control(vpiFinish, 1);
+	    vpi_free_object(argv);
 	    return 0;
       }
 
@@ -695,6 +696,7 @@ static PLI_INT32 sys_sscanf_compiletf(PLI_BYTE8*name)
 	    vpi_printf("%s's first argument must be a register or constant "
 	               "string.\n", name);
 	    vpi_control(vpiFinish, 1);
+	    vpi_free_object(argv);
 	    return 0;
       }
 

vpi/sys_vcd.c

@@ -805,6 +805,7 @@ static PLI_INT32 sys_dumpvars_calltf(PLI_BYTE8*name)
 		        vpi_printf("VCD warning: skipping signal %s, "
 		                   "it was previously included.\n",
 		                   fullname);
+		        free(scname);
 		        continue;
 		  } else {
 		        add_var = 1;