json-c: backport patch to fix gcc7 compilation

(The native version might be being built using gcc-7)

We can't cherry-pick a commit from master, as master
has upgraded json-c at the same time as applying
this patch, see commit
ccf630e78aad ("json-c: Upgrade to 0.12.1 release")

(From OE-Core rev: 9b0cb8149ce82c0e6fa3054b54d35e9bf1353bf0)

Signed-off-by: André Draszik <adraszik@tycoint.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/json-c/json-c/0001-Add-FALLTHRU-comment-to-handle-GCC7-warnings.patch

@@ -0,0 +1,77 @@
+From 9522ac8e5d5b20a472f3ffc356d388d36f7f582c Mon Sep 17 00:00:00 2001
+From: marxin <mliska@suse.cz>
+Date: Tue, 21 Mar 2017 08:42:11 +0100
+Subject: [PATCH] Add FALLTHRU comment to handle GCC7 warnings.
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+---
+Upstream-Status: Backport [https://github.com/json-c/json-c/commit/014924ba899f659917bb64392bbff7d3c803afc2]
+Signed-off-by: André Draszik <adraszik@tycoint.com>
+
+ json_object.c  |  1 +
+ json_tokener.c |  1 +
+ linkhash.c     | 22 +++++++++++-----------
+ 3 files changed, 13 insertions(+), 11 deletions(-)
+
+diff --git a/json_object.c b/json_object.c
+index 6cc73bc..77e8b21 100644
+--- a/json_object.c
++++ b/json_object.c
+@@ -552,6 +552,7 @@ int64_t json_object_get_int64(struct json_object *jso)
+     return jso->o.c_boolean;
+   case json_type_string:
+ 	if (json_parse_int64(jso->o.c_string.str, &cint) == 0) return cint;
++	/* FALLTHRU */
+   default:
+     return 0;
+   }
+diff --git a/json_tokener.c b/json_tokener.c
+index 7fa32ae..b32d657 100644
+--- a/json_tokener.c
++++ b/json_tokener.c
+@@ -306,6 +306,7 @@ struct json_object* json_tokener_parse_ex(struct json_tokener *tok,
+             tok->err = json_tokener_error_parse_unexpected;
+             goto out;
+         }
++	/* FALLTHRU */
+       case '"':
+ 	state = json_tokener_state_string;
+ 	printbuf_reset(tok->pb);
+diff --git a/linkhash.c b/linkhash.c
+index 712c387..74e3b0f 100644
+--- a/linkhash.c
++++ b/linkhash.c
+@@ -376,17 +376,17 @@ static uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
+     /*-------------------------------- last block: affect all 32 bits of (c) */
+     switch(length)                   /* all the case statements fall through */
+     {
+-    case 12: c+=((uint32_t)k[11])<<24;
+-    case 11: c+=((uint32_t)k[10])<<16;
+-    case 10: c+=((uint32_t)k[9])<<8;
+-    case 9 : c+=k[8];
+-    case 8 : b+=((uint32_t)k[7])<<24;
+-    case 7 : b+=((uint32_t)k[6])<<16;
+-    case 6 : b+=((uint32_t)k[5])<<8;
+-    case 5 : b+=k[4];
+-    case 4 : a+=((uint32_t)k[3])<<24;
+-    case 3 : a+=((uint32_t)k[2])<<16;
+-    case 2 : a+=((uint32_t)k[1])<<8;
++    case 12: c+=((uint32_t)k[11])<<24; /* FALLTHRU */
++    case 11: c+=((uint32_t)k[10])<<16; /* FALLTHRU */
++    case 10: c+=((uint32_t)k[9])<<8; /* FALLTHRU */
++    case 9 : c+=k[8]; /* FALLTHRU */
++    case 8 : b+=((uint32_t)k[7])<<24; /* FALLTHRU */
++    case 7 : b+=((uint32_t)k[6])<<16; /* FALLTHRU */
++    case 6 : b+=((uint32_t)k[5])<<8; /* FALLTHRU */
++    case 5 : b+=k[4]; /* FALLTHRU */
++    case 4 : a+=((uint32_t)k[3])<<24; /* FALLTHRU */
++    case 3 : a+=((uint32_t)k[2])<<16; /* FALLTHRU */
++    case 2 : a+=((uint32_t)k[1])<<8; /* FALLTHRU */
+     case 1 : a+=k[0];
+              break;
+     case 0 : return c;
+-- 
+2.14.1
+

meta/recipes-devtools/json-c/json-c_0.12.bb

@@ -7,6 +7,7 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=de54b60fbbc35123ba193fea8ee216f2"
 SRC_URI = "https://s3.amazonaws.com/json-c_releases/releases/${BP}.tar.gz \
            file://0001-json_tokener-requires-INF-and-NAN.patch \
            file://0001-Link-against-libm-when-needed.patch \
+           file://0001-Add-FALLTHRU-comment-to-handle-GCC7-warnings.patch \
           "
 
 SRC_URI[md5sum] = "3ca4bbb881dfc4017e8021b5e0a8c491"