atmel-samd: get most constrained m0 builds to work again

By tweaking the optimizer flags, we can get back a few hundred bytes
and allow these builds to work with the gcc9 compiler.

Author: jepler

ports/atmel-samd/Makefile

@@ -122,7 +122,12 @@ else
   ifdef CFLAGS_INLINE_LIMIT
     CFLAGS += -finline-limit=$(CFLAGS_INLINE_LIMIT)
   endif
+
   CFLAGS += -flto -flto-partition=none
+
+  ifdef CFLAGS_BOARD
+    CFLAGS += $(CFLAGS_BOARD)
+  endif
 endif
 
 CFLAGS += $(INC) -Wall -Werror -std=gnu11 -nostdlib $(BASE_CFLAGS) $(CFLAGS_MOD) $(COPT)

ports/atmel-samd/boards/pirkey_m0/mpconfigboard.mk

@@ -29,3 +29,5 @@ SUPEROPT_GC = 0
 FROZEN_MPY_DIRS += $(TOP)/frozen/Adafruit_CircuitPython_DotStar
 FROZEN_MPY_DIRS += $(TOP)/frozen/Adafruit_CircuitPython_HID
 FROZEN_MPY_DIRS += $(TOP)/frozen/Adafruit_CircuitPython_IRRemote
+
+CFLAGS_BOARD = --param inline-unit-growth=15 --param max-inline-insns-auto=20

ports/atmel-samd/boards/pyruler/mpconfigboard.mk

@@ -12,3 +12,5 @@ LONGINT_IMPL = NONE
 CIRCUITPY_SMALL_BUILD = 1
 
 SUPEROPT_GC = 0
+
+CFLAGS_BOARD = --param inline-unit-growth=15 --param max-inline-insns-auto=20

ports/atmel-samd/boards/trinket_m0/mpconfigboard.mk

@@ -12,3 +12,5 @@ LONGINT_IMPL = NONE
 CIRCUITPY_SMALL_BUILD = 1
 
 SUPEROPT_GC = 0
+
+CFLAGS_BOARD = --param inline-unit-growth=15 --param max-inline-insns-auto=20