Allow missing SONAME in .toc files

At least one shared object in internal repo doesn't have
SONAME entry in its dynamic segment because it is created by
objcopy instead of a linker.

Change-Id: If7106da022ff1e4e925191402f9072795dc3ddcb
diff --git a/core/config.mk b/core/config.mk
index 9c275f7..49810ee 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -283,7 +283,7 @@
 
 # Commands to generate .toc file common to ELF .so files.
 define _gen_toc_command_for_elf
-$(hide) $($(PRIVATE_2ND_ARCH_VAR_PREFIX)$(PRIVATE_PREFIX)READELF) -d $(1) | grep SONAME > $(2)
+$(hide) ($($(PRIVATE_2ND_ARCH_VAR_PREFIX)$(PRIVATE_PREFIX)READELF) -d $(1) | grep SONAME || echo "No SONAME for $1") > $(2)
 $(hide) $($(PRIVATE_2ND_ARCH_VAR_PREFIX)$(PRIVATE_PREFIX)NM) -gD -f p $(1) | cut -f1-2 -d" " >> $(2)
 endef