Added c++ linker command to allow to include libstdc++ when linking. (#276)

Added c++ linker command to allow to include libstdc++ when linking

Author: helmut64

Diff for: platform.txt

@@ -34,7 +34,7 @@ compiler.warning_flags.all=-Wall -Wextra
 compiler.path={runtime.tools.arm-none-eabi-gcc-4.8.3-2014q1.path}/bin/
 compiler.c.cmd=arm-none-eabi-gcc
 compiler.c.flags=-mcpu={build.mcu} -mthumb -c -g -Os {compiler.warning_flags} -std=gnu11 -ffunction-sections -fdata-sections -nostdlib --param max-inline-insns-single=500 -MMD
-compiler.c.elf.cmd=arm-none-eabi-gcc
+compiler.c.elf.cmd=arm-none-eabi-g++
 compiler.c.elf.flags=-Os -Wl,--gc-sections -save-temps
 compiler.S.cmd=arm-none-eabi-gcc
 compiler.S.flags=-c -g -x assembler-with-cpp -MMD