lkl: fix hijack and zpoline parallel builds

This is a follow up change for commit 3c97822 ("lkl: add tests
build barrier") tracked via #558.
The hijack and zpoline libraries also share object files, so need extra
logic to avoid parallel build failures.

Add a new intermediate libhijack-priv-in.o prerequisite for the
libraries, avoiding the .WAIT target which breaks make libraries_install
on older (e.g. 4.2.1) versions of make.

Signed-off-by: David Disseldorp <ddiss@suse.de>

Author: ddiss

tools/lkl/Makefile

@@ -89,7 +89,7 @@ $(OUTPUT)lib/lkl.o: bin/stat $(DOT_CONFIG)
 
 # rules to link libs
 $(OUTPUT)%$(SOSUF): LDFLAGS += -shared
-$(OUTPUT)%$(SOSUF): $(OUTPUT)%-in.o $(OUTPUT)liblkl.a
+$(OUTPUT)%$(SOSUF): $(priv-libs-y:%=$(OUTPUT)%-in.o) $(OUTPUT)%-in.o $(OUTPUT)liblkl.a
 	$(QUIET_LINK)$(CC) $(LDFLAGS) $(LDFLAGS_$*-y) -o $@ $^ $(LDLIBS) $(LDLIBS_$*-y)
 
 # liblkl is special
@@ -105,7 +105,6 @@ $(OUTPUT)%$(EXESUF): $(OUTPUT)%-in.o $(OUTPUT)liblkl.a
 $(OUTPUT)%-in.o: $(OUTPUT)lib/lkl.o FORCE
 	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=$(patsubst %/,%,$(dir $*)) obj=$(notdir $*)
 
-
 $(OUTPUT)cpfromfs$(EXESUF): cptofs$(EXESUF)
 	$(Q)if ! [ -e $@ ]; then ln -s $< $@; fi
 

tools/lkl/Targets

@@ -1,6 +1,7 @@
 libs-y += lib/liblkl
 
 ifneq ($(LKL_HOST_CONFIG_BSD),y)
+priv-libs-$(LKL_HOST_CONFIG_POSIX) += lib/hijack/libhijack-priv
 libs-$(LKL_HOST_CONFIG_POSIX) += lib/hijack/liblkl-hijack
 libs-$(LKL_HOST_CONFIG_POSIX) += lib/hijack/liblkl-zpoline
 endif

tools/lkl/lib/hijack/Build

@@ -1,14 +1,11 @@
+libhijack-priv-y += hijack.o
+libhijack-priv-y += init.o
+libhijack-priv-y += xlate.o
+libhijack-priv-y += dbg_handler.o
+
 liblkl-hijack-y += preload.o
-liblkl-hijack-y += hijack.o
-liblkl-hijack-y += init.o
-liblkl-hijack-y += xlate.o
-liblkl-hijack-y += dbg_handler.o
 
 liblkl-zpoline-y += zpoline.o
-liblkl-zpoline-y += hijack.o
-liblkl-zpoline-y += init.o
-liblkl-zpoline-y += xlate.o
-liblkl-zpoline-y += dbg_handler.o
 
 # -std=gnu23/c23 fails due to HOST_CALL (*host_##name)()
 CFLAGS_hijack.o += -std=gnu11