[XEN PATCH for-4.17 v5 03/17] tools: Introduce $(xenlibs-ldflags, ) macro

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

This avoid the need to open-coding the list of flags needed to link
with an in-tree Xen library when using -lxen*.

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
Reviewed-by: Henry Wang <Henry.Wang@xxxxxxx>
---

Notes:
    missing-ack: GOLANG BINDINGS

 tools/golang/xenlight/Makefile | 2 +-
 tools/Rules.mk                 | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/golang/xenlight/Makefile b/tools/golang/xenlight/Makefile
index 64671f246c..00e6d17f2b 100644
--- a/tools/golang/xenlight/Makefile
+++ b/tools/golang/xenlight/Makefile
@@ -27,7 +27,7 @@ GOXL_GEN_FILES = types.gen.go helpers.gen.go
 # so that it can find the actual library.
 .PHONY: build
 build: xenlight.go $(GOXL_GEN_FILES)
-       CGO_CFLAGS="$(CFLAGS_libxenlight) $(CFLAGS_libxentoollog) 
$(APPEND_CFLAGS)" CGO_LDFLAGS="$(LDLIBS_libxenlight) $(LDLIBS_libxentoollog) 
-L$(XEN_libxenlight) -L$(XEN_libxentoollog) $(APPEND_LDFLAGS)" $(GO) build -x
+       CGO_CFLAGS="$(CFLAGS_libxenlight) $(CFLAGS_libxentoollog) 
$(APPEND_CFLAGS)" CGO_LDFLAGS="$(call xenlibs-ldflags,light toollog) 
$(APPEND_LDFLAGS)" $(GO) build -x
 
 .PHONY: install
 install: build
diff --git a/tools/Rules.mk b/tools/Rules.mk
index ce77dd2eb1..26958b2948 100644
--- a/tools/Rules.mk
+++ b/tools/Rules.mk
@@ -105,6 +105,14 @@ define xenlibs-ldlibs
     $(foreach lib,$(1),$(xenlibs-ldlibs-$(lib)))
 endef
 
+# Provide needed flags for linking an in-tree Xen library by an external
+# project (or when it is necessary to link with "-lxen$(1)" instead of using
+# the full path to the library).
+define xenlibs-ldflags
+    $(call xenlibs-rpath,$(1)) \
+    $(foreach lib,$(1),-L$(XEN_ROOT)/tools/libs/$(lib))
+endef
+
 define LIB_defs
  FILENAME_$(1) ?= xen$(1)
  XEN_libxen$(1) = $$(XEN_ROOT)/tools/libs/$(1)
-- 
Anthony PERARD