support precompiled library with compiler.libraries.ldflags

Author: hathach

platform.txt

@@ -74,6 +74,7 @@ compiler.c.elf.extra_flags=
 compiler.cpp.extra_flags=
 compiler.S.extra_flags=
 compiler.ar.extra_flags=
+compiler.libraries.ldflags=
 compiler.elf2bin.extra_flags=
 compiler.elf2hex.extra_flags=
 
@@ -94,7 +95,7 @@ recipe.S.o.pattern="{compiler.path}{compiler.S.cmd}" {compiler.S.flags} -DF_CPU=
 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}"  "-L{build.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} "-L{build.core.path}/linker" "-T{build.ldscript}" "-Wl,-Map,{build.path}/{build.project_name}.map" {compiler.ldflags} -o "{build.path}/{build.project_name}.elf" {object_files} -Wl,--start-group -lm "{build.path}/{archive_file}" -Wl,--end-group
+recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" "-L{build.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} "-L{build.core.path}/linker" "-T{build.ldscript}" "-Wl,-Map,{build.path}/{build.project_name}.map" {compiler.ldflags} -o "{build.path}/{build.project_name}.elf" {object_files} {compiler.libraries.ldflags} -Wl,--start-group -lm "{build.path}/{archive_file}" -Wl,--end-group
 
 ## Create output (bin file)
 #recipe.objcopy.bin.pattern="{compiler.path}{compiler.elf2bin.cmd}" {compiler.elf2bin.flags} {compiler.elf2bin.extra_flags} "{build.path}/{build.project_name}.elf" "{build.path}/{build.project_name}.bin"