[PATCH] elf: Support lld-style link map for librtld.map

[Fangrui Song]

GNU ld and gold's -Map include a line like:

  path/to/build/libc_pic.a(check_fds.os)

lld -Map does not have the archive member list, but we can still derive the
members from the following output

             VMA              LMA     Size Align Out     In      Symbol
...
           1a1c0            1a1c0       e2    16         path/to/build/libc_pic.a(check_fds.os):(.text)

---
 elf/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/elf/Makefile b/elf/Makefile
index da689a2c7b..b035407112 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -512,9 +512,10 @@ $(objpfx)librtld.map: $(objpfx)dl-allobjs.os $(common-objpfx)libc_pic.a
 	rm -f $@.o
 	mv -f $@T $@
 
+# For lld, skip preceding addresses and values before matching the archive and the member.
 $(objpfx)librtld.mk: $(objpfx)librtld.map Makefile
 	LC_ALL=C \
-	sed -n 's@^$(common-objpfx)\([^(]*\)(\([^)]*\.os\)) *.*$$@\1 \2@p' \
+	sed -n 's@^[0-9a-f ]*$(common-objpfx)\([^(]*\)(\([^)]*\.os\)) *.*$$@\1 \2@p' \
 	    $< | \
 	while read lib file; do \
 	  case $$lib in \
-- 
2.25.1