toolchain: Add the possibility to have a mcpu option with wrapper

Permit to define the mcpu of the external toolchain wrapper, based on
BR2_GCC_TARGET_CPU.

Signed-off-by: Stany MARCEL <stanypub@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

toolchain/toolchain-external/ext-tool.mk

@@ -127,6 +127,7 @@ TOOLCHAIN_EXTERNAL_WRAPPER_ARGS = \
 	-DBR_SYSROOT='"$(STAGING_DIR)"'
 
 CC_TARGET_TUNE_:=$(call qstrip,$(BR2_GCC_TARGET_TUNE))
+CC_TARGET_CPU_:=$(call qstrip,$(BR2_GCC_TARGET_CPU))
 CC_TARGET_ARCH_:=$(call qstrip,$(BR2_GCC_TARGET_ARCH))
 CC_TARGET_ABI_:=$(call qstrip,$(BR2_GCC_TARGET_ABI))
 
@@ -140,6 +141,10 @@ ifneq ($(CC_TARGET_ARCH_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -march=$(CC_TARGET_ARCH_)
 TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_ARCH='"$(CC_TARGET_ARCH_)"'
 endif
+ifneq ($(CC_TARGET_CPU_),)
+TOOLCHAIN_EXTERNAL_CFLAGS += -mcpu=$(CC_TARGET_CPU_)
+TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_CPU='"$(CC_TARGET_CPU_)"'
+endif
 ifneq ($(CC_TARGET_ABI_),)
 TOOLCHAIN_EXTERNAL_CFLAGS += -mabi=$(CC_TARGET_ABI_)
 TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += -DBR_ABI='"$(CC_TARGET_ABI_)"'

toolchain/toolchain-external/ext-toolchain-wrapper.c

@@ -28,6 +28,9 @@ static char *predef_args[] = {
 #ifdef BR_TUNE
 	"-mtune=" BR_TUNE,
 #endif /* BR_TUNE */
+#ifdef BR_CPU
+	"-mcpu=" BR_CPU,
+#endif
 #ifdef BR_ABI
 	"-mabi=" BR_ABI,
 #endif