elfutils: fix building elfutils-native with GCC7

Backport a fix from upstream for a -Wformat-truncation=2 warning
and implement a simple fix for a -Wimplicit-fallthrough warning.

(From OE-Core rev: aaf4c4f3d09ac3897205417eb15e19d54e0c0d05)

Signed-off-by: Joshua Lock <joshua.g.lock@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/elfutils/elfutils-0.168/Fix_one_GCC7_warning.patch

@@ -0,0 +1,44 @@
+From 93c51144c3f664d4e9709da75a1d0fa00ea0fe95 Mon Sep 17 00:00:00 2001
+From: Mark Wielaard <mark@klomp.org>
+Date: Sun, 12 Feb 2017 21:51:34 +0100
+Subject: [PATCH] libasm: Fix one GCC7 -Wformat-truncation=2 warning.
+
+Make sure that if we have really lots of labels the tempsym doesn't get
+truncated because it is too small to hold the whole name.
+
+This doesn't enable -Wformat-truncation=2 or fix other "issues" pointed
+out by enabling this warning because there are currently some issues
+with it. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79448
+
+Signed-off-by: Mark Wielaard <mark@klomp.org>
+
+Upstream-Status: Backport (https://sourceware.org/git/?p=elfutils.git;a=commit;h=93c51144c3f664d4e9709da75a1d0fa00ea0fe95)
+Signed-off-by: Joshua Lock <joshua.g.lock@intel.com>
+
+---
+ libasm/ChangeLog    | 6 +++++-
+ libasm/asm_newsym.c | 6 ++++--
+ 2 files changed, 9 insertions(+), 3 deletions(-)
+
+Index: elfutils-0.168/libasm/asm_newsym.c
+===================================================================
+--- elfutils-0.168.orig/libasm/asm_newsym.c
++++ elfutils-0.168/libasm/asm_newsym.c
+@@ -1,5 +1,5 @@
+ /* Define new symbol for current position in given section.
+-   Copyright (C) 2002, 2005, 2016 Red Hat, Inc.
++   Copyright (C) 2002, 2005, 2016, 2017 Red Hat, Inc.
+    This file is part of elfutils.
+    Written by Ulrich Drepper <drepper@redhat.com>, 2002.
+ 
+@@ -44,7 +44,9 @@ AsmSym_t *
+ asm_newsym (AsmScn_t *asmscn, const char *name, GElf_Xword size,
+ 	    int type, int binding)
+ {
+-#define TEMPSYMLEN 10
++/* We don't really expect labels with many digits, but in theory it could
++   be 10 digits (plus ".L" and a zero terminator).  */
++#define TEMPSYMLEN 13
+   char tempsym[TEMPSYMLEN];
+   AsmSym_t *result;
+ 

meta/recipes-devtools/elfutils/elfutils-0.168/fallthrough.patch

@@ -0,0 +1,36 @@
+GCC7 adds -Wimplicit-fallthrough to warn when a switch case falls through,
+however this causes warnings (which are promoted to errors) with the elfutils
+patches from Debian for mips and parisc, which use fallthrough's by design.
+
+Explicitly mark the intentional fallthrough switch cases with a comment to
+disable the warnings where the fallthrough behaviour is desired.
+
+Upstream-Status: Pending [debian]
+Signed-off-by: Joshua Lock <joshua.g.lock@intel.com>
+
+Index: elfutils-0.168/backends/parisc_retval.c
+===================================================================
+--- elfutils-0.168.orig/backends/parisc_retval.c
++++ elfutils-0.168/backends/parisc_retval.c
+@@ -166,7 +166,7 @@ parisc_return_value_location_ (Dwarf_Die
+ 	  return nloc_intregpair;
+ 
+ 	/* Else fall through.  */
+-      }
++      } // fallthrough
+ 
+     case DW_TAG_structure_type:
+     case DW_TAG_class_type:
+Index: elfutils-0.168/backends/mips_retval.c
+===================================================================
+--- elfutils-0.168.orig/backends/mips_retval.c
++++ elfutils-0.168/backends/mips_retval.c
+@@ -387,7 +387,7 @@ mips_return_value_location (Dwarf_Die *f
+               else
+                 return nloc_intregpair;
+             }
+-        }
++        } // fallthrough
+ 
+       /* Fallthrough to handle large types */
+ 

meta/recipes-devtools/elfutils/elfutils_0.168.bb

@@ -17,6 +17,7 @@ SRC_URI += "\
         file://0001-remove-the-unneed-checking.patch \
         file://0001-fix-a-stack-usage-warning.patch \
         file://aarch64_uio.patch \
+        file://Fix_one_GCC7_warning.patch \
         file://shadow.patch \
 "
 
@@ -35,6 +36,8 @@ SRC_URI += "\
         file://debian/hurd_path.patch \
         file://debian/ignore_strmerge.diff \
 "
+# Fix the patches from Debian with GCC7
+SRC_URI += "file://fallthrough.patch"
 SRC_URI_append_libc-musl = " file://0001-build-Provide-alternatives-for-glibc-assumptions-hel.patch "
 
 # The buildsystem wants to generate 2 .h files from source using a binary it just built,