Merge pull request #10404 from cladmi/pr/arm/warning_on_ubuntu_bionic_gcc

cortexm.inc.mk: detect 'arm-none-eabi-gcc' from ubuntu bionic

makefiles/arch/cortexm.inc.mk

@@ -43,6 +43,32 @@ export USEMODULE += newlib
 # set default for CPU_MODEL
 export CPU_MODEL ?= $(CPU)
 
+
+# extract version inside the first parentheses
+ARM_GCC_VERSION = $(shell $(TARGET_ARCH)-gcc --version | sed -n '1 s/[^(]*(\([^\)]*\)).*/\1/p')
+
+# Ubuntu bionic gcc-arm-none-eabi compiler is not supported
+# Both when using gnu and llvm toolchains
+#
+#     /usr/bin/arm-none-eabi-gcc --version | head -n 1
+#     arm-none-eabi-gcc (15:6.3.1+svn253039-1build1) 6.3.1 20170620
+#
+ARM_GCC_UNSUPPORTED += 15:6.3.1%  # ubuntu bionic, ignore 'svn' build part
+
+# Should not raise an error on the host system version when building in docker
+ifneq (1,$(BUILD_IN_DOCKER))
+  ifneq (,$(filter $(ARM_GCC_UNSUPPORTED),$(ARM_GCC_VERSION)))
+    $(warning $(TARGET_ARCH)-gcc version not supported)
+    $(warning $(shell $(TARGET_ARCH)-gcc --version | head -n 1))
+    $(warning The currently recommanded version is the one installed in the riotdocker image)
+    $(warning https://github.com/RIOT-OS/riotdocker/blob/master/Dockerfile)
+    ifeq (1,$(WERROR))
+      $(error This check can be ignored by building with 'WERROR=0')
+    endif # WERROR
+  endif # ARM_GCC_UNSUPPORTED
+endif # BUILD_IN_DOCKER
+
+
 # Temporary LLVM/Clang Workaround:
 # report cortex-m0 instead of cortex-m0plus if llvm/clang (<= 3.6.2) is used
 # llvm/clang version 3.6.2 still does not support the cortex-m0plus mcpu type