Define __PROG_TYPES_COMPAT__

The regular arduino core uses some types like prog_char, which are
deprecated on newer avr-libc versions. Since the Pinoccio requires a
newer toolchain than is included with Arduino, this breaks.

A fix is pending in the Arduino repo, but until it is in a released IDE
version, this workaround should fix things. See also
arduino/Arduino#1695

Author: matthijskooijman

hardware/pinoccio/avr/boards.txt

@@ -21,6 +21,8 @@ pinoccio.build.f_cpu=16000000L
 pinoccio.build.core=arduino:arduino
 pinoccio.build.variant=pinoccio
 pinoccio.build.board=PINOCCIO
+# Workaround for https://github.com/arduino/Arduino/pull/1695
+pinoccio.build.extra_flags=-D__PROG_TYPES_COMPAT__
 
 ##############################################################
 pinoccio128.name=Pinoccio 128RFA1
@@ -45,3 +47,5 @@ pinoccio128.build.f_cpu=16000000L
 pinoccio128.build.core=arduino:arduino
 pinoccio128.build.variant=pinoccio
 pinoccio.build.board=PINOCCIO
+# Workaround for https://github.com/arduino/Arduino/pull/1695
+pinoccio.build.extra_flags=-D__PROG_TYPES_COMPAT__