add new official library.properties field for static linking flags

Author: kent-williams

platform.txt

@@ -26,6 +26,7 @@ compiler.ar.cmd=arm-none-eabi-gcc-ar
 compiler.c.elf.cmd=arm-none-eabi-gcc
 compiler.objcopy.cmd=arm-none-eabi-objcopy
 compiler.elf2hex.cmd=arm-none-eabi-objcopy
+compiler.libraries.ldflags=
 
 compiler.extra_flags=-mcpu={build.mcu} {build.flags.fp} -mthumb "@{build.opt.path}"
 
@@ -125,7 +126,7 @@ recipe.S.o.pattern="{compiler.path}{compiler.S.cmd}" {compiler.S.flags} {build.i
 recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} {compiler.ar.extra_flags} "{archive_file_path}" "{object_file}"
 
 ## Combine gc-sections, archives, and objects
-recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {compiler.c.elf.flags} "-T{build.variant.path}/{build.ldscript}" "-Wl,-Map,{build.path}/{build.project_name}.map" {compiler.c.elf.extra_flags} {compiler.ldflags} {compiler.arm.cmsis.ldflags} -o "{build.path}/{build.project_name}.elf" "-L{build.path}" -Wl,--start-group {object_files} "{archive_file_path}" -lc -Wl,--end-group -lm -lgcc -lstdc++
+recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {compiler.c.elf.flags} "-T{build.variant.path}/{build.ldscript}" "-Wl,-Map,{build.path}/{build.project_name}.map" {compiler.c.elf.extra_flags} {compiler.ldflags} {compiler.arm.cmsis.ldflags} -o "{build.path}/{build.project_name}.elf" "-L{build.path}" -Wl,--start-group {object_files} {compiler.libraries.ldflags} "{archive_file_path}" -lc -Wl,--end-group -lm -lgcc -lstdc++
 
 ## Create output (.bin file)
 recipe.objcopy.bin.pattern="{compiler.path}{compiler.objcopy.cmd}" {compiler.elf2bin.flags} {compiler.elf2bin.extra_flags} "{build.path}/{build.project_name}.elf" "{build.path}/{build.project_name}.bin"