CAM: Made empty spindle at the end optional in Fanuc CAM post processing script

Some Fanuc machines do not understand the 'M6 T0' instructions in the
preamble.  Move it out of the preamble and controlled by a new
command line argument --no-end-spindle-empty for the machines
where running to cause a "Tool Number Alarm" and the program to crash
as tool zero is not a valid tool.

Fixes: #25677

src/Mod/CAM/Path/Post/scripts/fanuc_post.py

@@ -67,7 +67,7 @@ parser.add_argument(
 )
 parser.add_argument(
     "--postamble",
-    help='set commands to be issued after the last command, default="M05\\nG17 G54 G90 G80 G40\\nM6 T0\\nM2\\n"',
+    help='set commands to be issued after the last command, default="M05\\nG17 G54 G90 G80 G40\\nM2\\n"',
 )
 parser.add_argument(
     "--inches", action="store_true", help="Convert output for US imperial mode (G20)"
@@ -85,6 +85,11 @@ parser.add_argument(
     action="store_true",
     help="suppress tool length offset (G43) following tool changes",
 )
+parser.add_argument(
+    "--no-end-spindle-empty",
+    action="store_true",
+    help="suppress putting last tool in tool change carousel before postamble",
+)
 
 TOOLTIP_ARGS = parser.format_help()
 
@@ -101,6 +106,8 @@ OUTPUT_DOUBLES = (
 COMMAND_SPACE = " "
 LINENR = 100  # line number starting value
 
+END_SPINDLE_EMPTY = True
+
 # These globals will be reflected in the Machine configuration of the project
 UNITS = "G21"  # G21 for metric, G20 for us standard
 UNIT_SPEED_FORMAT = "mm/min"
@@ -122,7 +129,6 @@ DEFAULT_PREAMBLE = """G17 G54 G40 G49 G80 G90
 # Postamble text will appear following the last operation.
 DEFAULT_POSTAMBLE = """M05
 G17 G54 G90 G80 G40
-M6 T0
 M2
 """
 
@@ -149,6 +155,7 @@ def processArguments(argstring):
     global UNIT_FORMAT
     global MODAL
     global USE_TLO
+    global END_SPINDLE_EMPTY
     global OUTPUT_DOUBLES
     global LINENR
 
@@ -204,6 +211,10 @@ def processArguments(argstring):
             OUTPUT_DOUBLES = True
         else:
             OUTPUT_DOUBLES = False
+        if args.no_end_spindle_empty:
+            END_SPINDLE_EMPTY = False
+        else:
+            END_SPINDLE_EMPTY = True
 
     except Exception:
         return False
@@ -294,6 +305,10 @@ def export(objectslist, filename, argstring):
                 gcode += linenumber() + "(COOLANT OFF:" + coolantMode.upper() + ")\n"
             gcode += linenumber() + "M9" + "\n"
 
+    if END_SPINDLE_EMPTY:
+        if OUTPUT_COMMENTS:
+            gcode += "(BEGIN MAKING SPINDLE EMPTY)\n"
+        gcode += "M05\nM6 T0\n"
     # do the post_amble
     if OUTPUT_COMMENTS:
         gcode += "(BEGIN POSTAMBLE)\n"