Add linker MAP artifact to standard build process (#4186)

Generate and preserve a linker .MAP file for the project in the usual
build directory.  This map file is useful for finding out where FLASH,
IROM, and IRAM are being used as it shows gcc internally generated
things such as jump tables and constant function-local variables.

platform.txt

@@ -89,7 +89,7 @@ recipe.S.o.pattern="{compiler.path}{compiler.c.cmd}" {compiler.cpreprocessor.fla
 recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} {compiler.ar.extra_flags} "{build.path}/arduino.ar" "{object_file}"
 
 ## Combine gc-sections, archives, and objects
-recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} -o "{build.path}/{build.project_name}.elf" -Wl,--start-group {object_files} "{build.path}/arduino.ar" {compiler.c.elf.libs} -Wl,--end-group  "-L{build.path}"
+recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" -Wl,-Map "-Wl,{build.path}/{build.project_name}.map" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} -o "{build.path}/{build.project_name}.elf" -Wl,--start-group {object_files} "{build.path}/arduino.ar" {compiler.c.elf.libs} -Wl,--end-group  "-L{build.path}"
 
 ## Create eeprom
 recipe.objcopy.eep.pattern=