patch 8.0.1295: cannot automatically get a server name in a terminal

Problem:    Cannot automatically get a server name in a terminal.
Solution:   Add the --enable-autoservername flag to configure. (Cimbali,
            closes #2317)
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index f2abcbd..f754892 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -8820,6 +8820,7 @@
 arabic			Compiled with Arabic support |Arabic|.
 arp			Compiled with ARP support (Amiga).
 autocmd			Compiled with autocommand support. |autocommand|
+autoservername		Automatically enable |clientserver|
 balloon_eval		Compiled with |balloon-eval| support.
 balloon_multiline	GUI supports multiline balloons.
 beos			BeOS version of Vim.
diff --git a/runtime/doc/various.txt b/runtime/doc/various.txt
index d994e71..07ec3b1 100644
--- a/runtime/doc/various.txt
+++ b/runtime/doc/various.txt
@@ -309,6 +309,7 @@
    *+ARP*		Amiga only: ARP support included
 B  *+arabic*		|Arabic| language support
 N  *+autocmd*		|:autocmd|, automatic commands
+H  *+autoservername*	Automatically enable |clientserver|
 m  *+balloon_eval*	|balloon-eval| support. Included when compiling with
 			supported GUI (Motif, GTK, GUI) and either
 			Netbeans/Sun Workshop integration or |+eval| feature.
diff --git a/src/Makefile b/src/Makefile
index 1cdacf9..f544528 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -570,6 +570,9 @@
 # This disables the dialog that asks you if you want to save files or not.
 #CONF_OPT_XSMP = --disable-xsmp-interact
 
+# If you want to always automatically add a servername, also in the terminal.
+#CONF_OPT_AUTOSERVE = --enable-autoservername
+
 # COMPILER - Name of the compiler {{{1
 # The default from configure will mostly be fine, no need to change this, just
 # an example. If a compiler is defined here, configure will use it rather than
@@ -1866,7 +1869,7 @@
 		CC="$(CC)" CPPFLAGS="$(CPPFLAGS)" CFLAGS="$(CFLAGS)" \
 		LDFLAGS="$(LDFLAGS)" $(CONF_SHELL) srcdir="$(srcdir)" \
 		./configure $(CONF_OPT_GUI) $(CONF_OPT_X) $(CONF_OPT_XSMP) \
-		$(CONF_OPT_DARWIN) $(CONF_OPT_FAIL) \
+		$(CONF_OPT_AUTOSERVE) $(CONF_OPT_DARWIN) $(CONF_OPT_FAIL) \
 		$(CONF_OPT_PERL) $(CONF_OPT_PYTHON) $(CONF_OPT_PYTHON3) \
 		$(CONF_OPT_TCL) $(CONF_OPT_RUBY) $(CONF_OPT_NLS) \
 		$(CONF_OPT_CSCOPE) $(CONF_OPT_MULTIBYTE) $(CONF_OPT_INPUT) \
diff --git a/src/auto/configure b/src/auto/configure
index 16cbcf3..f4cd8b4 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -817,6 +817,7 @@
 enable_netbeans
 enable_channel
 enable_terminal
+enable_autoservername
 enable_multibyte
 enable_hangulinput
 enable_xim
@@ -1495,6 +1496,7 @@
   --disable-netbeans      Disable NetBeans integration support.
   --disable-channel       Disable process communication support.
   --enable-terminal       Enable terminal emulation support.
+  --enable-autoservername Automatically define servername at vim startup.
   --enable-multibyte      Include multibyte editing support.
   --enable-hangulinput    Include Hangul input support.
   --enable-xim            Include XIM input support.
@@ -7516,6 +7518,22 @@
 
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking --enable-autoservername argument" >&5
+$as_echo_n "checking --enable-autoservername argument... " >&6; }
+# Check whether --enable-autoservername was given.
+if test "${enable_autoservername+set}" = set; then :
+  enableval=$enable_autoservername;
+else
+  enable_autoservername="no"
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $enable_autoservername" >&5
+$as_echo "$enable_autoservername" >&6; }
+if test "$enable_autoservername" = "yes"; then
+  $as_echo "#define FEAT_AUTOSERVERNAME 1" >>confdefs.h
+
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking --enable-multibyte argument" >&5
 $as_echo_n "checking --enable-multibyte argument... " >&6; }
 # Check whether --enable-multibyte was given.
diff --git a/src/config.h.in b/src/config.h.in
index e692d40..ec9fc59 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -384,6 +384,9 @@
 /* Define if you want to include multibyte support. */
 #undef FEAT_MBYTE
 
+/* Define if you want to always define a server name at vim startup. */
+#undef FEAT_AUTOSERVERNAME
+
 /* Define if you want to include fontset support. */
 #undef FEAT_XFONTSET
 
diff --git a/src/configure.ac b/src/configure.ac
index e287124..7277f87 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -2066,6 +2066,15 @@
   AC_SUBST(TERM_OBJ)
 fi
 
+AC_MSG_CHECKING(--enable-autoservername argument)
+AC_ARG_ENABLE(autoservername,
+	[  --enable-autoservername Automatically define servername at vim startup.], ,
+	[enable_autoservername="no"])
+AC_MSG_RESULT($enable_autoservername)
+if test "$enable_autoservername" = "yes"; then
+  AC_DEFINE(FEAT_AUTOSERVERNAME)
+fi
+
 AC_MSG_CHECKING(--enable-multibyte argument)
 AC_ARG_ENABLE(multibyte,
 	[  --enable-multibyte      Include multibyte editing support.], ,
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 5e22fe4..1991aa7 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -5580,6 +5580,9 @@
 #ifdef FEAT_AUTOCMD
 	"autocmd",
 #endif
+#ifdef FEAT_AUTOSERVERNAME
+	"autoservername",
+#endif
 #ifdef FEAT_BEVAL
 	"balloon_eval",
 # ifndef FEAT_GUI_W32 /* other GUIs always have multiline balloons */
diff --git a/src/feature.h b/src/feature.h
index e90d755..d100d6b 100644
--- a/src/feature.h
+++ b/src/feature.h
@@ -1168,6 +1168,14 @@
 #endif
 
 /*
+ * +autoservername	Automatically generate a servername for clientserver
+ *			when --servername is not passed on the command line.
+ */
+#if defined(FEAT_CLIENTSERVER) && !defined(FEAT_AUTOSERVERNAME)
+/* # define FEAT_AUTOSERVERNAME */
+#endif
+
+/*
  * +termresponse	send t_RV to obtain terminal response.  Used for xterm
  *			to check if mouse dragging can be used and if term
  *			codes can be obtained.
diff --git a/src/main.c b/src/main.c
index 97f1b03..e8006c3 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3673,12 +3673,18 @@
     /*
      * Register for remote command execution with :serversend and --remote
      * unless there was a -X or a --servername '' on the command line.
-     * Only register nongui-vim's with an explicit --servername argument.
+     * Only register nongui-vim's with an explicit --servername argument,
+     * or when compiling with autoservername.
      * When running as root --servername is also required.
      */
     if (X_DISPLAY != NULL && parmp->servername != NULL && (
-#  ifdef FEAT_GUI
-		(gui.in_use
+#  if defined(FEAT_AUTOSERVERNAME) || defined(FEAT_GUI)
+		(
+#   if defined(FEAT_AUTOSERVERNAME)
+		    1
+#   else
+		    gui.in_use
+#   endif
 #   ifdef UNIX
 		 && getuid() != ROOT_UID
 #   endif
diff --git a/src/version.c b/src/version.c
index 1fd6502..2c190a6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -83,6 +83,11 @@
 #else
 	"-autocmd",
 #endif
+#ifdef FEAT_AUTOSERVERNAME
+	"+autoservername",
+#else
+	"-autoservername",
+#endif
 #ifdef FEAT_BEVAL
 	"+balloon_eval",
 #else
@@ -762,6 +767,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1295,
+/**/
     1294,
 /**/
     1293,