included amj40 implementation of nhou7 from https://github.com/nhou7/qmk_firmware_amj40

keyboards/amj40/keymaps/default/build.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+# adjust for cpu 
+# -j 16 gave best result on a hyperthreaded quad core core i7
+
+LIMIT=10
+THREADS="-j 16"
+KMAP=iso_split_rshift
+
+echo "We need sudo later"
+sudo ls 2>&1 /dev/null
+
+function wait_bootloader {
+	echo "Waiting for Bootloader..."
+	local STARTTIME=$(date +"%s")
+	local REMIND=0
+    local EXEC=dfu-programmer
+    local TARGET=atmega32u4
+	while true
+	do
+		sudo $EXEC $TARGET get > /dev/null 2>&1
+		[ $? -eq 0 ] && break
+		ENDTIME=$(date +"%s")
+		DURATION=$(($ENDTIME-$STARTTIME))
+		if [ $REMIND -eq 0 -a $DURATION -gt $LIMIT ]
+		then 
+			echo "Did you forget to press the reset button?"
+			REMIND=1
+		fi
+        sleep 1
+	done
+}
+make clean
+make KEYMAP=${KMAP} ${THREADS}
+if [[ $? -eq 0 ]]
+then
+    echo "please trigger flashing!"
+    wait_bootloader
+    sudo make KEYMAP=${KMAP} dfu ${THREADS}
+else
+    echo "make failed"
+    exit 77
+fi