Add preprocessing of linker script

This allow to use switch in ldscript.ld file.

Signed-off-by: Frederic.Pillon <[email protected]>

Author: fpistm

platform.txt

@@ -93,6 +93,11 @@ recipe.hooks.prebuild.1.pattern.windows=cmd /c if not exist "{build.opt.sourcepa
 recipe.hooks.prebuild.1.pattern.linux=bash -c "[ -f {build.opt.sourcepath} ] || (mkdir -p {build.path}/sketch && touch {build.opt.path})"
 recipe.hooks.prebuild.1.pattern.macosx=bash -c "[ -f {build.opt.sourcepath} ] || (mkdir -p {build.path}/sketch && touch {build.opt.path})"
 
+# preprocess linker file
+preprocld.name=preproc.ld
+preprocld.filepath={build.path}/{preprocld.name}
+recipe.hooks.linking.prelink.1.pattern="{compiler.path}{compiler.c.cmd}" -x c -E -P {compiler.c.flags} {build.info.flags} {compiler.c.extra_flags} {build.extra_flags} {compiler.arm.cmsis.c.flags} "{build.variant.path}/{build.ldscript}" -o "{preprocld.filepath}"
+
 # compile patterns
 # ---------------------
 
@@ -109,7 +114,7 @@ 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} -Wl,--whole-archive "{archive_file_path}" -Wl,--no-whole-archive -lc -Wl,--end-group -lm -lgcc -lstdc++
+recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {compiler.c.elf.flags} "-T{preprocld.filepath}" "-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} -Wl,--whole-archive "{archive_file_path}" -Wl,--no-whole-archive -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"