source https://www.vogons.org/viewtopic.php?f=61&t=71459
--- orig/src/libc/go32/exceptn.S        2002-12-21 21:08:39.000000000 -0800
+++ ./src/libc/go32/exceptn.S 2020-01-18 18:37:27.397176800 -0800
@@ -337,6 +337,15 @@
        je      6f
        orb     $2,%ah  /* If RShift is set, set LShift as well */
 6:
+        movb    %ah,%al
+       andb    %cs:___djgpp_sigint_mask, %ah   /* Mask off irrelevant bits */
+       cmpb    %cs:___djgpp_sigint_key+1, %ah  /* Test for SIGINT */
+        je      60f
+        movb    %al,%ah
+       andb    %cs:___djgpp_sigquit_mask, %ah  /* Mask off irrelevant bits */
+       cmpb    %cs:___djgpp_sigquit_key+1, %ah /* Test for SIGQUIT*/
+       jne     Lkbd_chain
+60:
        inb     $0x60,%al                       /* Read the scan code */
 99:
        movb    %ah,%bh                         /* Save KB status */