have_func: checking for rb_enc_raise() in ruby.h... -------------------- yes

"gcc -o conftest -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/json/parser    -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fPIC conftest.c  -L. -L../../.. -L. -Wl,-rpath=/opt/cpanel/ea-ruby27/root/usr/lib64 -fstack-protector-strong -rdynamic -Wl,-export-dynamic  -m64   -lruby-static -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 -o conftest -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/json/parser    -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fPIC conftest.c  -L. -L../../.. -L. -Wl,-rpath=/opt/cpanel/ea-ruby27/root/usr/lib64 -fstack-protector-strong -rdynamic -Wl,-export-dynamic  -m64   -lruby-static -lpthread -lrt -lrt -ldl -lcrypt -lm   -lm   -lc"
conftest.c: In function 't':
conftest.c:16:57: error: 'rb_enc_raise' undeclared (first use in this function); did you mean 'rb_exc_raise'?
 int t(void) { void ((*volatile p)()); p = (void ((*)()))rb_enc_raise; return !p; }
                                                         ^~~~~~~~~~~~
                                                         rb_exc_raise
conftest.c:16:57: note: each undeclared identifier is reported only once for each function it appears in
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: #include <ruby.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 ((*)()))rb_enc_raise; return !p; }
/* end */

"gcc -o conftest -I../../../.ext/include/x86_64-linux -I../../.././include -I../../.././ext/json/parser    -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fPIC conftest.c  -L. -L../../.. -L. -Wl,-rpath=/opt/cpanel/ea-ruby27/root/usr/lib64 -fstack-protector-strong -rdynamic -Wl,-export-dynamic  -m64   -lruby-static -lpthread -lrt -lrt -ldl -lcrypt -lm   -lm   -lc"
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: #include <ruby.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: extern void rb_enc_raise();
17: int t(void) { rb_enc_raise(); return 0; }
/* end */

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

extconf.h is:
/* begin */
1: #ifndef EXTCONF_H
2: #define EXTCONF_H
3: #define HAVE_RB_ENC_RAISE 1
4: #endif
/* end */