Added gdb recipe for openocd

Author: cmaglie

boards.txt

@@ -20,6 +20,7 @@ arduino_zero_edbg.name=Arduino Zero (Programming Port)
 arduino_zero_edbg.vid.0=0x03eb
 arduino_zero_edbg.pid.0=0x2157
 
+arduino_zero_edbg.debug.tool=gdb
 arduino_zero_edbg.upload.tool=openocd
 arduino_zero_edbg.upload.protocol=sam-ba
 arduino_zero_edbg.upload.maximum_size=262144

platform.txt

@@ -113,8 +113,8 @@ recipe.output.save_file={build.project_name}.{build.variant}.{build.preferred_ou
 recipe.size.pattern="{compiler.path}{compiler.size.cmd}" -A "{build.path}/{build.project_name}.elf"
 recipe.size.regex=\.text\s+([0-9]+).*
 
-# Uploader tools
-# --------------
+# Upload/Debug tools
+# ------------------
 
 #
 # AVRDUDE
@@ -219,3 +219,13 @@ tools.openocd-withbootsize.erase.pattern=
 tools.openocd-withbootsize.bootloader.params.verbose=-d2
 tools.openocd-withbootsize.bootloader.params.quiet=-d0
 tools.openocd-withbootsize.bootloader.pattern="{path}/{cmd}" {bootloader.verbose} -s "{path}/share/openocd/scripts/" -f "{runtime.platform.path}/variants/{build.variant}/{build.openocdscript}" -c "telnet_port disabled; init; halt; at91samd bootloader 0; program {{runtime.platform.path}/bootloaders/{bootloader.file}} verify reset; shutdown"
+
+#
+# GDB (Debugger)
+#
+
+tools.gdb.path={runtime.tools.arm-none-eabi-gcc-7-2017q4.path}/bin/
+tools.gdb.cmd=arm-none-eabi-gdb
+tools.gdb.cmd.windows=arm-none-eabi-gdb.exe
+
+tools.gdb.debug.pattern="{path}/{cmd}" -ex 'target extended-remote | {tools.openocd.path}/{tools.openocd.cmd} -s "{tools.openocd.path}/share/openocd/scripts/" -f "{runtime.platform.path}/variants/{build.variant}/{build.openocdscript}" -c "gdb_port pipe" -c "telnet_port 0" -c init -c halt'