[build] Don't use rodso.ld with lld

With lld's -z rodynamic, it's now possible to do the "rodso" cases (the
vDSO and userboot) without using the scripts/rodso.ld linker script.

Change-Id: I30cb10a23e71878f524f04f30c4834c108c90efd

make/engine.mk

@@ -195,6 +195,9 @@ USER_LDFLAGS := \
 
 ifeq ($(call TOBOOL,$(USE_LLD)),true)
 USER_LDFLAGS += -z rodynamic
+RODSO_LDFLAGS :=
+else
+RODSO_LDFLAGS := -T scripts/rodso.ld
 endif
 
 ifeq ($(call TOBOOL,$(USE_LTO)),true)

system/core/userboot/rules.mk

@@ -90,6 +90,6 @@ GENERATED += $(BUILDDIR)/$(LOCAL_DIR)/vdso-syms.ld.h
 MODULE_EXTRA_OBJS := $(BUILDDIR)/$(LOCAL_DIR)/vdso-syms.ld
 
 # userboot is a reentrant DSO (no writable segment) with an entry point.
-MODULE_LDFLAGS := -T scripts/rodso.ld -e _start
+MODULE_LDFLAGS := $(RODSO_LDFLAGS) -e _start
 
 include make/module.mk

system/ulib/magenta/rules.mk

@@ -47,7 +47,7 @@ MODULE_SO_INSTALL_NAME := -
 # All the code this DSO is pure read-only/reentrant code that
 # does not need any writable data (except its caller's stack).
 # Make it use a simplified, hardened memory layout.
-MODULE_LDFLAGS := -T scripts/rodso.ld
+MODULE_LDFLAGS := $(RODSO_LDFLAGS)
 
 # Explicit dependency to make sure the file gets generated first.
 # MODULE_SRCDEPS is overkill for this since only one file uses it.