Fix:
conftest.c:99:3: error: implicitly declaring library function 'exit' with type 'void (int) __attribute__((noreturn))' [-Werror,-Wimplicit-function-declaration]
https://github.com/agraef/pure-lang/pull/38
--- configure.orig	2018-04-11 01:25:26.000000000 -0500
+++ configure	2022-09-19 22:28:17.000000000 -0500
@@ -7378,7 +7378,7 @@
   set_signal_handler(SIGINT, sigint);
   kill((int)getpid(), SIGINT);
   kill((int)getpid(), SIGINT);
-  exit(nsigint != 2);
+  return (nsigint != 2);
 }
 
 _ACEOF
