[PATCH] Makefile: libfdt: build only the strict necessary

[Claudio Fontana <cfontana@suse.de>]

when building dtc/libfdt, we were previously using dtc/Makefile,
which tries to build some artifacts that are not needed,
and can complain on stderr about the absence of tools that
are not required to build just libfdt.

Instead, build only the strict necessary to get libfdt.a .

Remove the subdir-dtc "compatibility gunk" for recursion,
since we are not recursing anymore.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
---
 Makefile  | 21 ++++++++++-----------
 configure |  6 +-----
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/Makefile b/Makefile
index 84ef881600..8a461534d9 100644
--- a/Makefile
+++ b/Makefile
@@ -526,15 +526,16 @@ $(SOFTMMU_FUZZ_RULES): $(edk2-decompressed)
 $(TARGET_DIRS_RULES):
 	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $(dir $@) V="$(V)" TARGET_DIR="$(dir $@)" $(notdir $@),)
 
-DTC_MAKE_ARGS=-I$(SRC_PATH)/dtc VPATH=$(SRC_PATH)/dtc -C dtc V="$(V)" LIBFDT_srcdir=$(SRC_PATH)/dtc/libfdt
-DTC_CFLAGS=$(CFLAGS) $(QEMU_CFLAGS)
-DTC_CPPFLAGS=-I$(BUILD_DIR)/dtc -I$(SRC_PATH)/dtc -I$(SRC_PATH)/dtc/libfdt
-
-.PHONY: dtc/all
-dtc/all: .git-submodule-status dtc/libfdt dtc/tests
-	$(call quiet-command,$(MAKE) $(DTC_MAKE_ARGS) CPPFLAGS="$(DTC_CPPFLAGS)" CFLAGS="$(DTC_CFLAGS)" LDFLAGS="$(QEMU_LDFLAGS)" ARFLAGS="$(ARFLAGS)" CC="$(CC)" AR="$(AR)" LD="$(LD)" $(SUBDIR_MAKEFLAGS) libfdt/libfdt.a,)
-
-dtc/%: .git-submodule-status
+LIBFDT_srcdir = $(SRC_PATH)/dtc/libfdt
+LIBFDT_objdir = dtc/libfdt
+LIBFDT_archive = $(LIBFDT_objdir)/libfdt.a
+include $(LIBFDT_srcdir)/Makefile.libfdt
+LIBFDT_objects = $(addprefix $(LIBFDT_objdir)/, $(LIBFDT_OBJS))
+.PHONY: libfdt
+libfdt: .git-submodule-status $(LIBFDT_archive)
+$(LIBFDT_archive): $(LIBFDT_objects)
+$(LIBFDT_objects): | $(LIBFDT_objdir)
+$(LIBFDT_objdir): .git-submodule-status
 	@mkdir -p $@
 
 # Overriding CFLAGS causes us to lose defines added in the sub-makefile.
@@ -563,7 +564,6 @@ slirp/all: .git-submodule-status
 
 # Compatibility gunk to keep make working across the rename of targets
 # for recursion, to be removed some time after 4.1.
-subdir-dtc: dtc/all
 subdir-capstone: capstone/all
 subdir-slirp: slirp/all
 
@@ -821,7 +821,6 @@ distclean: clean
 	rm -rf $$d || exit 1 ; \
         done
 	rm -Rf .sdk
-	if test -f dtc/version_gen.h; then $(MAKE) $(DTC_MAKE_ARGS) clean; fi
 
 KEYMAPS=da     en-gb  et  fr     fr-ch  is  lt  no  pt-br  sv \
 ar      de     en-us  fi  fr-be  hr     it  lv  nl         pl  ru     th \
diff --git a/configure b/configure
index 22870f3867..eb50d50b0a 100755
--- a/configure
+++ b/configure
@@ -4278,10 +4278,6 @@ EOF
       if test -d "${source_path}/dtc/libfdt" || test -e "${source_path}/.git" ; then
           fdt=git
           mkdir -p dtc
-          if [ "$pwd_is_source_path" != "y" ] ; then
-              symlink "$source_path/dtc/Makefile" "dtc/Makefile"
-              symlink "$source_path/dtc/scripts" "dtc/scripts"
-          fi
           fdt_cflags="-I\$(SRC_PATH)/dtc/libfdt"
           fdt_ldflags="-L\$(BUILD_DIR)/dtc/libfdt"
           fdt_libs="$fdt_libs"
@@ -8151,7 +8147,7 @@ echo "PIXMAN_CFLAGS=$pixman_cflags" >> $config_host_mak
 echo "PIXMAN_LIBS=$pixman_libs" >> $config_host_mak
 
 if [ "$fdt" = "git" ]; then
-  echo "config-host.h: dtc/all" >> $config_host_mak
+  echo "config-host.h: libfdt" >> $config_host_mak
 fi
 if [ "$capstone" = "git" -o "$capstone" = "internal" ]; then
   echo "config-host.h: capstone/all" >> $config_host_mak
-- 
2.16.4