mk: avoid trigraph warnings by adding -Wno-trigraphs

mk/board_native.mk

@@ -25,7 +25,7 @@ DEFINES        +=   -DSKETCH=\"$(SKETCH)\" -DSKETCHNAME="\"$(SKETCH)\"" -DSKETCH
 DEFINES        +=   $(EXTRAFLAGS)
 DEFINES        +=   -DCONFIG_HAL_BOARD=$(HAL_BOARD) -DCONFIG_HAL_BOARD_SUBTYPE=$(HAL_BOARD_SUBTYPE)
 WARNFLAGS       =   -Wall -Wextra -Wformat -Wshadow -Wpointer-arith -Wcast-align \
-                    -Wlogical-op -Wwrite-strings -Wformat=2 -Wno-unused-parameter -Wno-unknown-pragmas
+                    -Wlogical-op -Wwrite-strings -Wformat=2 -Wno-unused-parameter -Wno-unknown-pragmas -Wno-trigraphs
 WARNFLAGSCXX    = \
         -Wno-missing-field-initializers \
         -Wno-reorder \
@@ -36,8 +36,8 @@ WARNFLAGSCXX    = \
         -Werror=init-self \
         -Wfatal-errors \
         -Wundef \
-        -Wno-unknown-warning-option
-
+        -Wno-unknown-warning-option \
+        -Wno-trigraphs
 DEPFLAGS        =   -MD -MP -MT $@
 
 CXXOPTS         =   -ffunction-sections -fdata-sections -fno-exceptions -fsigned-char

mk/px4_targets.mk

@@ -51,7 +51,7 @@ PX4_V4PRO_CONFIG_FILE=$(MK_DIR)/PX4/config_px4fmu-v4pro_APM.mk
 # because this platform lacks most of the standard library and STL. Hence we need to force C++03 mode.
 SKETCHFLAGS=$(SKETCHLIBINCLUDES) -DUAVCAN_CPP_VERSION=UAVCAN_CPP03 -DUAVCAN_NO_ASSERTIONS -DUAVCAN_NULLPTR=nullptr -DARDUPILOT_BUILD -DTESTS_MATHLIB_DISABLE -DCONFIG_HAL_BOARD=HAL_BOARD_PX4 -DSKETCHNAME="\\\"$(SKETCH)\\\"" -DSKETCH_MAIN=ArduPilot_main -DAPM_BUILD_DIRECTORY=APM_BUILD_$(SKETCH)
 
-WARNFLAGS = -Wall -Wextra -Wlogical-op -Werror -Wno-attributes -Wno-unknown-pragmas -Wno-redundant-decls -Wno-psabi -Wno-packed -Wno-error=double-promotion -Wno-error=unused-variable -Wno-error=reorder -Wno-error=float-equal -Wno-error=pmf-conversions -Wno-error=missing-declarations -Wno-error=unused-function
+WARNFLAGS = -Wall -Wextra -Wlogical-op -Werror -Wno-attributes -Wno-unknown-pragmas -Wno-redundant-decls -Wno-psabi -Wno-packed -Wno-error=double-promotion -Wno-error=unused-variable -Wno-error=reorder -Wno-error=float-equal -Wno-error=pmf-conversions -Wno-error=missing-declarations -Wno-error=unused-function -Wno-trigraphs
 OPTFLAGS = -fsingle-precision-constant
 
 # avoid PX4 submodules

mk/vrbrain_targets.mk

@@ -58,7 +58,7 @@ VRUBRAIN_V52_CONFIG_FILE=config_vrubrain-v52_APM.mk
 
 SKETCHFLAGS=$(SKETCHLIBINCLUDES) -DARDUPILOT_BUILD -DTESTS_MATHLIB_DISABLE -DCONFIG_HAL_BOARD=HAL_BOARD_VRBRAIN -DSKETCHNAME="\\\"$(SKETCH)\\\"" -DSKETCH_MAIN=ArduPilot_main -DAPM_BUILD_DIRECTORY=APM_BUILD_$(SKETCH)
 
-WARNFLAGS = -Wall -Wextra -Wlogical-op -Werror -Wno-unknown-pragmas -Wno-redundant-decls -Wno-psabi -Wno-packed -Wno-error=double-promotion -Wno-error=unused-variable -Wno-error=reorder -Wno-error=float-equal -Wno-error=pmf-conversions -Wno-error=missing-declarations -Wno-error=unused-function
+WARNFLAGS = -Wall -Wextra -Wlogical-op -Werror -Wno-unknown-pragmas -Wno-redundant-decls -Wno-psabi -Wno-packed -Wno-error=double-promotion -Wno-error=unused-variable -Wno-error=reorder -Wno-error=float-equal -Wno-error=pmf-conversions -Wno-error=missing-declarations -Wno-error=unused-function -Wno-trigraphs
 OPTFLAGS = -fsingle-precision-constant
 
 # avoid VRBRAIN submodules