Fixing linker command line argument.

Author: damellis

hardware/arduino/platforms.txt

@@ -43,7 +43,7 @@ avr.name=Arduino
 #avr.compiler.path={0}/hardware/tools/avr/bin/
 avr.compiler.c.cmd=avr-gcc
 avr.compiler.c.flags=|-c|-g|-Os|-w|-ffunction-sections|-fdata-sections
-avr.compiler.c.elf.flags=|-Os|-Wl|--gc-sections
+avr.compiler.c.elf.flags=|-Os|-Wl,--gc-sections
 avr.compiler.c.elf.cmd=avr-gcc
 avr.compiler.S.flags=|-c|-g|-assembler-with-cpp
 avr.compiler.cpp.cmd=avr-g++