Depend on ECJPAKE key exchange, not module

This is more consistent, as it doesn't make any sense for a user to be able to
set up an EC J-PAKE password with TLS if the corresponding key exchange is
disabled.

Arguably this is what we should de for other key exchanges as well instead of
depending on ECDH_C etc, but this is an independent issue, so let's just do
the right thing with the new key exchange and fix the other ones later. (This
is a marginal issue anyway, since people who disable all ECDH key exchange are
likely to also disable ECDH_C in order to minimize footprint.)
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 04c3098..3d73da9 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1676,7 +1676,7 @@
                   void *p_sni );
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 /**
  * \brief          Set the EC J-PAKE password for current handshake.
  *
@@ -1697,7 +1697,7 @@
 int mbedtls_ssl_set_hs_ecjpake_password( mbedtls_ssl_context *ssl,
                                          const unsigned char *pw,
                                          size_t pw_len );
-#endif /*MBEDTLS_ECJPAKE_C */
+#endif /*MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_SSL_ALPN)
 /**
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index dc2ddc1..d9e3e5c 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -41,7 +41,7 @@
 #include "sha512.h"
 #endif
 
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 #include "ecjpake.h"
 #endif
 
@@ -172,11 +172,11 @@
 #if defined(MBEDTLS_ECDH_C)
     mbedtls_ecdh_context ecdh_ctx;              /*!<  ECDH key exchange       */
 #endif
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     mbedtls_ecjpake_context ecjpake_ctx;        /*!< EC J-PAKE key exchange */
 #endif
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
-    defined(MBEDTLS_ECJPAKE_C)
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     const mbedtls_ecp_curve_info **curves;      /*!<  Supported elliptic curves */
 #endif
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index e8cb0f1..2d32071 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -209,7 +209,7 @@
           MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
-    defined(MBEDTLS_ECJPAKE_C)
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 static void ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
                                                      unsigned char *buf,
                                                      size_t *olen )
@@ -278,9 +278,9 @@
 
     *olen = 6;
 }
-#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_ECJPAKE_C */
+#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
                                         unsigned char *buf,
                                         size_t *olen )
@@ -320,7 +320,7 @@
 
     *olen = kkpp_len + 4;
 }
-#endif /* MBEDTLS_ECJPAKE_C */
+#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
@@ -821,7 +821,7 @@
 #endif
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
-    defined(MBEDTLS_ECJPAKE_C)
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
 
@@ -829,7 +829,7 @@
     ext_len += olen;
 #endif
 
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
 #endif
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index afac3e1..67dad5f 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -1977,7 +1977,7 @@
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
-    defined(MBEDTLS_ECJPAKE_C)
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
                                                    unsigned char *buf,
                                                    size_t *olen )
@@ -2005,7 +2005,7 @@
 
     *olen = 6;
 }
-#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_ECJPAKE_C */
+#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_SSL_ALPN )
 static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
@@ -2292,7 +2292,7 @@
 #endif
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
-    defined(MBEDTLS_ECJPAKE_C)
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
 #endif
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 2f5ca9f..84211bb 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -4932,7 +4932,7 @@
 #if defined(MBEDTLS_ECDH_C)
     mbedtls_ecdh_init( &handshake->ecdh_ctx );
 #endif
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     mbedtls_ecjpake_init( &handshake->ecjpake_ctx );
 #endif
 
@@ -5451,7 +5451,7 @@
 }
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 /*
  * Set EC J-PAKE password for current handshake
  */
@@ -5475,7 +5475,7 @@
                                    MBEDTLS_ECP_DP_SECP256R1,
                                    pw, pw_len ) );
 }
-#endif /* MBEDTLS_ECJPAKE_C */
+#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
 int mbedtls_ssl_conf_psk( mbedtls_ssl_config *conf,
@@ -6619,7 +6619,7 @@
 #if defined(MBEDTLS_ECDH_C)
     mbedtls_ecdh_free( &handshake->ecdh_ctx );
 #endif
-#if defined(MBEDTLS_ECJPAKE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     mbedtls_ecjpake_free( &handshake->ecjpake_ctx );
 #endif