patch 8.1.1386: unessesary type casts for lalloc()

Problem:    Unessesary type casts for lalloc().
Solution:   Remove type casts.  Change lalloc(size, TRUE) to alloc(size).
diff --git a/src/os_unix.c b/src/os_unix.c
index 0ec48a1..803f944 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -4459,9 +4459,9 @@
 	else
 	    x = system((char *)cmd);
 # else
-	newcmd = lalloc(STRLEN(p_sh)
+	newcmd = alloc(STRLEN(p_sh)
 		+ (extra_shell_arg == NULL ? 0 : STRLEN(extra_shell_arg))
-		+ STRLEN(p_shcf) + STRLEN(cmd) + 4, TRUE);
+		+ STRLEN(p_shcf) + STRLEN(cmd) + 4);
 	if (newcmd == NULL)
 	    x = 0;
 	else