[Buildroot] [PATCH v5 2/5] Makefile: add HOST_FIX_RPATH_HOOK to TARGET_FINALIZE_HOOKS

[Samuel Martin <s.martin49@gmail.com>]

This patch adds host-patchelf as a target-finalize dependency, and
introduces the HOST_FIX_RPATH_HOOK hook fixing the ELF files' RPATH of
the HOST_DIR location (excluding the sysroot).

After running this hook, the RPATH from any host ELF files is relative to
the binary location itself.

Note that, we avoid to fix RPATH in the sysroot, and in the external
toolcahin installation location.

As a first step toward a fully relocatable SDK, this change allows to get
the toolchain relocatable, but not yet the whole SDK.

Signed-off-by: Samuel Martin <s.martin49@gmail.com>

---
changes v4->v5:
- add verbose support

changes v3->v4:
- add host-patchelf to PACKAGES instead of target-finalize (Baruch)
- add comment

changes v2->v3:
- move hook in Makefile (Baruch)
---
 Makefile | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Makefile b/Makefile
index 546bcd3..4b88116 100644
--- a/Makefile
+++ b/Makefile
@@ -555,6 +555,22 @@ endef
 TARGET_FINALIZE_HOOKS += PURGE_LOCALES
 endif
 
+# RPATH fixing
+# - The host hook sets RPATH in host ELF binaries, using relative paths to the
+#   library locations.
+PACKAGES += host-patchelf
+
+define HOST_FIX_RPATH_HOOK
+	$(TOPDIR)/support/scripts/fix_rpaths \
+		set $(HOST_DIR) \
+		$(if $(V),--verbose) \
+		--patchelf-program $(HOST_DIR)/usr/bin/patchelf \
+		--libdirs $(HOST_DIR)/usr/lib \
+		--exclude-dirs sysroot opt/ext-toolchain
+endef
+
+TARGET_FINALIZE_HOOKS += HOST_FIX_RPATH_HOOK
+
 $(TARGETS_ROOTFS): target-finalize
 
 target-finalize: $(PACKAGES)
-- 
2.4.5