patch 8.1.1207: some compilers give warning messages

Problem:    Some compilers give warning messages.
Solution:   Initialize variables, change printf() argument. (Christian
            Brabandt, closes #4305)

src/eval.c

@@ -4051,7 +4051,7 @@ eval6(
     varnumber_T	n1, n2;
 #ifdef FEAT_FLOAT
     int		use_float = FALSE;
-    float_T	f1 = 0, f2;
+    float_T	f1 = 0, f2 = 0;
 #endif
     int		error = FALSE;
 

src/screen.c

@@ -549,8 +549,8 @@ update_screen(int type_arg)
 #endif
 #ifdef FEAT_GUI
     int		did_undraw = FALSE;
-    int		gui_cursor_col;
-    int		gui_cursor_row;
+    int		gui_cursor_col = 0;
+    int		gui_cursor_row = 0;
 #endif
     int		no_update = FALSE;
 

src/undo.c

@@ -2271,7 +2271,7 @@ undo_time(
     u_header_T	    *uhp = NULL;
     u_header_T	    *last;
     int		    mark;
-    int		    nomark;
+    int		    nomark = 0;  // shut up compiler
     int		    round;
     int		    dosec = sec;
     int		    dofile = file;

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1207,
 /**/
     1206,
 /**/

src/window.c

@@ -3981,7 +3981,7 @@ enter_tabpage(
     void
 goto_tabpage(int n)
 {
-    tabpage_T	*tp;
+    tabpage_T	*tp = NULL;  // shut up compiler
     tabpage_T	*ttp;
     int		i;