"gcc -o conftest -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/io/console    -g -O2 -fPIC conftest.c  -L. -L../../.. -L. -fstack-protector-strong -rdynamic -Wl,-export-dynamic     -Wl,-rpath,/usr/local/rvm/rubies/ruby-2.7.4/lib -L/usr/local/rvm/rubies/ruby-2.7.4/lib -lruby-static -lz -lpthread -lrt -lrt -ldl -lcrypt -lm   -lm   -lc"
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main(int argc, char **argv)
4: {
5:   return !!argv[argc];
6: }
/* end */

"gcc -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/io/console    -g -O2 -fPIC   -c conftest.c"
conftest.c:5:3: error: #error 
 # error
   ^~~~~
conftest.c:6:1: error: expected identifier or ‘(’ before ‘|’ token
 |:/ === _WIN32 undefined === /:|
 ^
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: /*top*/
4: #ifndef _WIN32
5: # error
6: |:/ === _WIN32 undefined === /:|
7: #endif
/* end */

have_header: checking for termios.h... -------------------- yes

"gcc -E -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/io/console    -g -O2 -fPIC  conftest.c -o conftest.i"
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: #include <termios.h>
/* end */

--------------------

have_func: checking for cfmakeraw() in termios.h... -------------------- yes

"gcc -o conftest -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/io/console    -g -O2 -fPIC conftest.c  -L. -L../../.. -L. -fstack-protector-strong -rdynamic -Wl,-export-dynamic     -Wl,-rpath,/usr/local/rvm/rubies/ruby-2.7.4/lib -L/usr/local/rvm/rubies/ruby-2.7.4/lib -lruby-static -lz -lpthread -lrt -lrt -ldl -lcrypt -lm   -lm   -lc"
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: #include <termios.h>
 4: 
 5: /*top*/
 6: extern int t(void);
 7: int main(int argc, char **argv)
 8: {
 9:   if (argc > 1000000) {
10:     int (* volatile tp)(void)=(int (*)(void))&t;
11:     printf("%d", (*tp)());
12:   }
13: 
14:   return !!argv[argc];
15: }
16: int t(void) { void ((*volatile p)()); p = (void ((*)()))cfmakeraw; return !p; }
/* end */

--------------------

have_header: checking for sys/ioctl.h... -------------------- yes

"gcc -E -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/io/console    -g -O2 -fPIC  conftest.c -o conftest.i"
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: #include <sys/ioctl.h>
/* end */

--------------------

extconf.h is:
/* begin */
1: #ifndef EXTCONF_H
2: #define EXTCONF_H
3: #define HAVE_TERMIOS_H 1
4: #define HAVE_CFMAKERAW 1
5: #define HAVE_SYS_IOCTL_H 1
6: #define ENABLE_IO_GETPASS 1
7: #endif
/* end */