gc-libgcrypt: fix undefined enum type in switch statement

Resolve the following build failure:
lib/gc-libgcrypt.c: In function 'gc_hash_open':
lib/gc-libgcrypt.c:317:5: error: case value '0' not in enumerated type
'Gc_hash_mode {aka enum Gc_hash_mode}' [-Werror=switch]
     case 0:
     ^~~~

* lib/gc.h (enum Gc_hash_mode): Add value GC_NULL.
* lib/gc-libgcrypt.c (gc_hash_open): Use this enum value instead of 0.

Signed-off-by: Jia Zhang <qianyue.zj@alibaba-inc.com>

3 files changed, 15 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 7191bd018b..2c6b8d16cf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,17 @@
 2017-10-28  Jia Zhang  <qianyue.zj@alibaba-inc.com>
 
+	gc-libgcrypt: fix undefined enum type in switch statement
+	Resolve the following build failure:
+	lib/gc-libgcrypt.c: In function 'gc_hash_open':
+	lib/gc-libgcrypt.c:317:5: error: case value '0' not in enumerated type
+	'Gc_hash_mode {aka enum Gc_hash_mode}' [-Werror=switch]
+	     case 0:
+	     ^~~~
+	* lib/gc.h (enum Gc_hash_mode): Add value GC_NULL.
+	* lib/gc-libgcrypt.c (gc_hash_open): Use this enum value instead of 0.
+
+2017-10-28  Jia Zhang  <qianyue.zj@alibaba-inc.com>
+
 	gc-libgcrypt: fix assignment error due to -Werror=pointer-sign
 	Resolve the following build failure:
 	lib/gc-libgcrypt.c: In function 'gc_hash_read':
diff --git a/lib/gc-libgcrypt.c b/lib/gc-libgcrypt.c
index 968b599926..f0c8d82293 100644
--- a/lib/gc-libgcrypt.c
+++ b/lib/gc-libgcrypt.c
@@ -310,7 +310,7 @@ gc_hash_open (Gc_hash hash, Gc_hash_mode mode, gc_hash_handle * outhandle)
 
   switch (mode)
     {
-    case 0:
+    case GC_NULL:
       gcrymode = 0;
       break;
 
diff --git a/lib/gc.h b/lib/gc.h
index 14f3e3c091..a47cc8d0e3 100644
--- a/lib/gc.h
+++ b/lib/gc.h
@@ -53,7 +53,8 @@ typedef enum Gc_hash Gc_hash;
 
 enum Gc_hash_mode
 {
-  GC_HMAC = 1
+  GC_NULL,
+  GC_HMAC
 };
 typedef enum Gc_hash_mode Gc_hash_mode;