Added experimental support for M98 subroutines, internal subroutines are only supported for programs run from a local file system.

$700 controls whether they are scanned for internally in the main program (1) or always located externally (0).
If scanned for internally the program is run twice, initially in check mode to locate the subroutines before it is rewound and run in normal mode.
If stored externally the file P<macro number>.macro is run, <macro number> is the M98 P value.

gcode.h

@@ -3,7 +3,7 @@
 
   Part of grblHAL
 
-  Copyright (c) 2017-2025 Terje Io
+  Copyright (c) 2017-2026 Terje Io
   Copyright (c) 2011-2016 Sungeun K. Jeon for Gnea Research LLC
   Copyright (c) 2009-2011 Simen Svale Skogsrud
 
@@ -28,6 +28,7 @@
 #include "coolant_control.h"
 #include "spindle_control.h"
 #include "errors.h"
+#include "vfs.h"
 
 #define MAX_OFFSET_ENTRIES 4 // must be a power of 2
 
@@ -60,6 +61,7 @@ typedef enum {
     Modal_MacroCall = 66,                   //!< 66 - G66
     Modal_MacroEnd = 67,                    //!< 67 - G67
     NonModal_SetCoordinateOffset = 92,      //!< 92 - G92
+    NonModal_MacroCall2 = 98,               //!< 98 - M98
     NonModal_ResetCoordinateOffset = 102,   //!< 102 - G92.1
     NonModal_ClearCoordinateOffset = 112,   //!< 112 - G92.2
  #if ENABLE_ACCELERATION_PROFILES
@@ -741,6 +743,7 @@ void gc_coolant (coolant_state_t state);
 void gc_set_tool_offset (tool_offset_mode_t mode, uint_fast8_t idx, int32_t offset);
 plane_t *gc_get_plane_data (plane_t *plane, plane_select_t select);
 axes_signals_t gc_claim_axis_words (parser_block_t *gc_block, axes_signals_t validate);
+size_t gc_macro_get_pos (macro_id_t id, vfs_file_t *file);
 
 #if NGC_PARAMETERS_ENABLE
 parameter_words_t gc_get_g65_arguments (void);