rules: provide default C and C++ standards

Default CSTD to c99, no default for CXXSTD, but if provided it will be used.

Add required gnu99 flags to projects using gnu styles.

examples/rules.mk

@@ -43,6 +43,7 @@ STYLECHECK	:= /checkpatch.pl
 STYLECHECKFLAGS	:= --no-tree -f --terse --mailback
 STYLECHECKFILES	:= $(shell find . -name '*.[ch]')
 OPT		:= -Os
+CSTD		?= -std=c99
 
 
 ###############################################################################
@@ -96,7 +97,7 @@ SCRIPT_DIR	= $(OPENCM3_DIR)/scripts
 ###############################################################################
 # C flags
 
-TGT_CFLAGS	+= $(OPT) -g
+TGT_CFLAGS	+= $(OPT) $(CSTD) -g
 TGT_CFLAGS	+= $(ARCH_FLAGS)
 TGT_CFLAGS	+= -Wextra -Wshadow -Wimplicit-function-declaration
 TGT_CFLAGS	+= -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes
@@ -105,7 +106,7 @@ TGT_CFLAGS	+= -fno-common -ffunction-sections -fdata-sections
 ###############################################################################
 # C++ flags
 
-TGT_CXXFLAGS	+= $(OPT) -g
+TGT_CXXFLAGS	+= $(OPT) $(CXXSTD) -g
 TGT_CXXFLAGS	+= $(ARCH_FLAGS)
 TGT_CXXFLAGS	+= -Wextra -Wshadow -Wredundant-decls  -Weffc++
 TGT_CXXFLAGS	+= -fno-common -ffunction-sections -fdata-sections

examples/stm32/f0/stm32f0-discovery/usart_stdio/Makefile

@@ -18,6 +18,7 @@
 ##
 
 BINARY = usart_stdio
+CSTD = -std=gnu99
 
 LDSCRIPT = ../stm32f0-discovery.ld
 

examples/stm32/f1/lisa-m-1/usb_dfu/Makefile

@@ -18,6 +18,7 @@
 ##
 
 BINARY = usbdfu
+CSTD = -std=gnu99
 
 LDSCRIPT = ../lisa-m.ld
 

examples/stm32/f1/lisa-m-2/adc_injec/Makefile

@@ -21,7 +21,6 @@ BINARY = adc_injec
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/adc_injec_timtrig/Makefile

@@ -21,7 +21,6 @@ BINARY = adc_injec_timtrig
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/adc_injec_timtrig_irq/Makefile

@@ -21,7 +21,6 @@ BINARY = adc_injec_timtrig_irq
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/adc_injec_timtrig_irq_4ch/Makefile

@@ -21,7 +21,6 @@ BINARY = adc_injec_timtrig_irq_4ch
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/adc_regular/Makefile

@@ -21,7 +21,6 @@ BINARY = adc
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/can/Makefile

@@ -21,7 +21,6 @@ BINARY = can
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/fancyblink/Makefile

@@ -21,7 +21,6 @@ BINARY = fancyblink
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/spi/Makefile

@@ -21,7 +21,6 @@ BINARY = spi
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/spi_dma/Makefile

@@ -21,7 +21,6 @@ BINARY = spi_dma
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/spi_dma_adv/Makefile

@@ -21,7 +21,6 @@ BINARY = spi_dma_adv
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/usart/Makefile

@@ -21,7 +21,6 @@ BINARY = usart
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/usart_dma/Makefile

@@ -21,7 +21,6 @@ BINARY = usart_dma
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/usart_irq/Makefile

@@ -21,7 +21,6 @@ BINARY = usart_irq
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/usart_irq_printf/Makefile

@@ -21,7 +21,6 @@ BINARY = usart_irq_printf
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/lisa-m-2/usart_printf/Makefile

@@ -21,7 +21,6 @@ BINARY = usart_printf
 
 # Comment the following line if you _don't_ have luftboot flashed!
 LDFLAGS += -Wl,-Ttext=0x8002000
-CFLAGS += -std=c99
 LDSCRIPT = ../lisa-m.ld
 
 include ../../Makefile.include

examples/stm32/f1/other/usb_dfu/Makefile

@@ -18,6 +18,7 @@
 ##
 
 BINARY = usbdfu
+CSTD = -std=gnu99
 
 include ../../Makefile.include
 

examples/stm32/f1/stm32-h103/usb_dfu/Makefile

@@ -18,6 +18,7 @@
 ##
 
 BINARY = usbdfu
+CSTD = -std=gnu99
 
 LDSCRIPT = ../stm32-h103.ld
 

examples/stm32/f1/stm32-h103/usb_iap/Makefile

@@ -18,6 +18,7 @@
 ##
 
 BINARY = usbiap
+CSTD = -std=gnu99
 
 LDSCRIPT = ../stm32-h103.ld
 

examples/stm32/f4/stm32f429i-discovery/lcd-dma/Makefile

@@ -1,6 +1,7 @@
 OBJS = sdram.o clock.o console.o lcd-spi.o
 
 BINARY = lcd-dma
+CSTD = -std=gnu99
 
 # we use sin/cos from the library
 LDLIBS += -lm