Massdrop keyboard updates for SEND_STRING, syscalls, stdio, debug prints, Auto Shift (#3973)

* Update for SEND_STRING usage

Update for SEND_STRING usage.
Sending keyboard reports (kbd, nkro) now obey the minimum polling time.
While attempting to send a keyboard report and waiting for a USB poll, other functions of the keyboard, including LED effects and power management, will continue to operate at their intended intervals.

* Updates for send string, syscalls, stdio, debug prints, auto shift

Now properly waiting for previous keys sent over USB to complete before sending new.
Added heap to linker and now compiling with syscalls support.
Removed custom string functions and now using stdio.
dprintf now works as intended through virtser device.

* CTRL and ALT keymap updates

CTRL mac keymap updated
ALT default and mac keymap updated
ALT rules.mk added Auto Shift with default no

* Code cleanup as per discussion with vomindoraan

Code cleanup as per discussion with vomindoraan

1 files changed, 10 insertions, 0 deletions

diff --git a/tmk_core/protocol/arm_atsam/d51_util.h b/tmk_core/protocol/arm_atsam/d51_util.h
index 465889c7cb..7a35f7989f 100644
--- a/tmk_core/protocol/arm_atsam/d51_util.h
+++ b/tmk_core/protocol/arm_atsam/d51_util.h
@@ -32,6 +32,16 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define m15_on  REG_PORT_OUTSET1 = 0x40000000 //PB30 High
 #define m15_off REG_PORT_OUTCLR1 = 0x40000000 //PB30 Low
 
+//Debug Port PB23
+#define m27_ena REG_PORT_DIRSET1 = 0x800000 //PB23 Output
+#define m27_on  REG_PORT_OUTSET1 = 0x800000 //PB23 High
+#define m27_off REG_PORT_OUTCLR1 = 0x800000 //PB23 Low
+
+//Debug Port PB31
+#define m28_ena REG_PORT_DIRSET1 = 0x80000000 //PB31 Output
+#define m28_on  REG_PORT_OUTSET1 = 0x80000000 //PB31 High
+#define m28_off REG_PORT_OUTCLR1 = 0x80000000 //PB31 Low
+
 #define m15_loop(M15X) {uint8_t M15L=M15X; while(M15L--){m15_on;CLK_delay_us(1);m15_off;}}
 
 void m15_print(uint32_t x);