patch 8.2.1215: Atari MiNT support is outdated

Problem:    Atari MiNT support is outdated.
Solution:   Nobody responded this code is still useful, so let's delete it.
diff --git a/src/os_unix.c b/src/os_unix.c
index a82256c..c9b3f92 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -3505,9 +3505,8 @@
 	// ~IXON disables CTRL-S stopping output, so that it can be mapped.
 	tnew.c_iflag &= ~(ICRNL | IXON);
 	tnew.c_lflag &= ~(ICANON | ECHO | ISIG | ECHOE
-# if defined(IEXTEN) && !defined(__MINT__)
+# if defined(IEXTEN)
 		    | IEXTEN	    // IEXTEN enables typing ^V on SOLARIS
-				    // but it breaks function keys on MINT
 # endif
 				);
 # ifdef ONLCR