perf: Add libunwind only if selected

package/devel/perf/Makefile

@@ -10,7 +10,7 @@ include $(INCLUDE_DIR)/kernel.mk
 
 PKG_NAME:=perf
 PKG_VERSION:=$(LINUX_VERSION)
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_USE_MIPS16:=0
 PKG_BUILD_PARALLEL:=1
@@ -26,7 +26,7 @@ include $(INCLUDE_DIR)/package.mk
 define Package/perf
   SECTION:=devel
   CATEGORY:=Development
-  DEPENDS:= +libelf1 +libdw +(mips||mipsel||powerpc||i386||x86_64||arm||aarch64):libunwind +libpthread +librt +objdump @!LINUX_3_18 @!IN_SDK @!TARGET_arc770 @KERNEL_PERF_EVENTS
+  DEPENDS:= +libelf +libdw +PACKAGE_libunwind:libunwind +libpthread +librt +objdump @!IN_SDK @!TARGET_arc770 @KERNEL_PERF_EVENTS
   TITLE:=Linux performance monitoring tool
   VERSION:=$(LINUX_VERSION)-$(PKG_RELEASE)
   URL:=http://www.kernel.org
@@ -36,10 +36,6 @@ define Package/perf/description
   perf is the Linux performance monitoring tool
 endef
 
-define Build/Prepare
-	$(CP) $(LINUX_DIR)/tools/perf/* $(PKG_BUILD_DIR)/
-endef
-
 MAKE_FLAGS = \
 	ARCH="$(LINUX_KARCH)" \
 	NO_LIBPERL=1 \
@@ -59,13 +55,13 @@ MAKE_FLAGS = \
 	LDFLAGS="$(TARGET_LDFLAGS)" \
 	$(if $(findstring c,$(OPENWRT_VERBOSE)),V=1,V='') \
 	WERROR=0 \
+	O=$(PKG_BUILD_DIR) \
 	prefix=/usr
 
 define Build/Compile
 	+$(MAKE_FLAGS) $(MAKE) $(PKG_JOBS) \
-		-C $(PKG_BUILD_DIR) \
-		-f Makefile.perf \
-		--no-print-directory
+		--no-print-directory \
+		-C $(LINUX_DIR)/tools/perf
 endef
 
 define Package/perf/install