[PATCH] kbuild: cmd_export_list: tighten the sed script

[Nicolas Pitre]

When LTO is used, some ___ksymtab_string sections are seen by this sed
script, creating lines containing a single ) such as:

EXPORT(foo)
)
)
EXPORT(bar)

Let's make it so the + character is also required for any line to be
printed.

Signed-off-by: Nicolas Pitre <nico@xxxxxxxxxx>

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 53b43f26bb..3066c8e61d 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -428,7 +428,7 @@ endif
 
 quiet_cmd_export_list = EXPORTS $@
 cmd_export_list = $(OBJDUMP) -h $< | \
-	sed -ne '/___ksymtab/{s/.*+/$(ref_prefix)/;s/ .*/)/;p}' >$(ksyms-lds);\
+	sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
 	rm -f $(dummy-object);\
 	$(AR) rcs$(KBUILD_ARFLAGS) $(dummy-object);\
 	$(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\