Move SCRAM-related name definitions to scram-common.h

Mechanism names for SCRAM and channel binding names have been included
in scram.h by the libpq frontend code, and this header references a set
of routines which are only used by the backend.  scram-common.h is on
the contrary usable by both the backend and libpq, so getting those
names from there seems more reasonable.

Author: Michael Paquier <michael.paquier@gmail.com>

src/backend/libpq/auth.c

@@ -26,6 +26,7 @@
 #include "commands/user.h"
 #include "common/ip.h"
 #include "common/md5.h"
+#include "common/scram-common.h"
 #include "libpq/auth.h"
 #include "libpq/crypt.h"
 #include "libpq/libpq.h"

src/include/common/scram-common.h

@@ -15,6 +15,13 @@
 
 #include "common/sha2.h"
 
+/* Name of SCRAM mechanisms per IANA */
+#define SCRAM_SHA256_NAME "SCRAM-SHA-256"
+#define SCRAM_SHA256_PLUS_NAME "SCRAM-SHA-256-PLUS" /* with channel binding */
+
+/* Channel binding types */
+#define SCRAM_CHANNEL_BINDING_TLS_UNIQUE    "tls-unique"
+
 /* Length of SCRAM keys (client and server) */
 #define SCRAM_KEY_LEN				PG_SHA256_DIGEST_LENGTH
 

src/include/libpq/scram.h

@@ -13,13 +13,6 @@
 #ifndef PG_SCRAM_H
 #define PG_SCRAM_H
 
-/* Name of SCRAM mechanisms per IANA */
-#define SCRAM_SHA256_NAME "SCRAM-SHA-256"
-#define SCRAM_SHA256_PLUS_NAME "SCRAM-SHA-256-PLUS" /* with channel binding */
-
-/* Channel binding types */
-#define SCRAM_CHANNEL_BINDING_TLS_UNIQUE	"tls-unique"
-
 /* Status codes for message exchange */
 #define SASL_EXCHANGE_CONTINUE		0
 #define SASL_EXCHANGE_SUCCESS		1

src/interfaces/libpq/fe-auth-scram.c

@@ -17,7 +17,6 @@
 #include "common/base64.h"
 #include "common/saslprep.h"
 #include "common/scram-common.h"
-#include "libpq/scram.h"
 #include "fe-auth.h"
 
 /* These are needed for getpid(), in the fallback implementation */

src/interfaces/libpq/fe-auth.c

@@ -39,8 +39,8 @@
 #endif
 
 #include "common/md5.h"
+#include "common/scram-common.h"
 #include "libpq-fe.h"
-#include "libpq/scram.h"
 #include "fe-auth.h"