patch 9.1.1270: missing out-of-memory checks in buffer.c

Problem:  missing out-of-memory checks in buffer.c
Solution: handle out-of-memory situations during allocation
          (John Marriott)

closes: #17031

Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/buffer.c

@@ -2926,6 +2926,8 @@ ExpandBufnames(
 		p = home_replace_save(buf, p);
 	    else
 		p = vim_strsave(p);
+	    if (p == NULL)
+		return FAIL;
 
 	    if (!fuzzy)
 	    {
@@ -4030,9 +4032,12 @@ maketitle(void)
 	    else
 	    {
 		p = transstr(gettail(curbuf->b_fname));
+		if (p != NULL)
+		{
 		    vim_strncpy(buf, p, SPACE_FOR_FNAME);
 		    vim_free(p);
 		}
+	    }
 
 #ifdef FEAT_TERMINAL
 	    if (curbuf->b_term == NULL)
@@ -4084,9 +4089,12 @@ maketitle(void)
 		if (off < SPACE_FOR_DIR)
 		{
 		    p = transstr(buf + off);
+		    if (p != NULL)
+		    {
 			vim_strncpy(buf + off, p, (size_t)(SPACE_FOR_DIR - off));
 			vim_free(p);
 		    }
+		}
 		else
 		{
 		    vim_strncpy(buf + off, (char_u *)"...",
@@ -4767,6 +4775,9 @@ build_stl_str_hl(
 		size_t new_fmt_len = parsed_usefmt
 						 + str_length + fmt_length + 3;
 		char_u *new_fmt = (char_u *)alloc(new_fmt_len * sizeof(char_u));
+
+		if (new_fmt != NULL)
+		{
 		    char_u *new_fmt_p = new_fmt;
 
 		    new_fmt_p = (char_u *)memcpy(new_fmt_p, usefmt, parsed_usefmt)
@@ -4787,6 +4798,7 @@ build_stl_str_hl(
 		    evaldepth++;
 		    continue;
 		}
+	    }
 #endif
 	    break;
 	}

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1270,
 /**/
     1269,
 /**/