assembly compile recipe is missing (C. A. Church)

Fixes #1457

Author: cmaglie

build/shared/revisions.txt

@@ -17,6 +17,7 @@ ARDUINO 1.5.3 BETA
 * avr: Added support for Flash strings on String class (Jantje)
 * Added support for floating point numbers in String class (Tevin Zhang, SebiTimeWaster)
 * sam: Fixed String buffer overflows (Paul Stoffregen)
+* avr: Added recipe for assembly files (C. A. Church)
 
 [libraries]
 * sam: Added CAN library (still in early stage of development) (Palliser)

hardware/arduino/avr/platform.txt

@@ -40,6 +40,9 @@ recipe.c.o.pattern="{compiler.path}{compiler.c.cmd}" {compiler.c.flags} -mmcu={b
 ## Compile c++ files
 recipe.cpp.o.pattern="{compiler.path}{compiler.cpp.cmd}" {compiler.cpp.flags} -mmcu={build.mcu} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {build.extra_flags} {includes} "{source_file}" -o "{object_file}"
 
+## Compile S files
+recipe.S.o.pattern="{compiler.path}{compiler.c.cmd}" {compiler.S.flags} -mmcu={build.mcu} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {build.extra_flags} {includes} "{source_file}" -o "{object_file}"
+
 ## Create archives
 recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} "{build.path}/{archive_file}" "{object_file}"