have_library: checking for main() in -lsocket... -------------------- no

"gcc -o conftest -I/opt/alt/ruby23/include/ruby-2.3.0/x86_64-linux -I/opt/alt/ruby23/include/ruby-2.3.0/ruby/backward -I/opt/alt/ruby23/include/ruby-2.3.0 -I.    -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 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection conftest.c  -L. -L/opt/alt/ruby23/lib64 -Wl,-rpath,/opt/alt/ruby23/lib64 -L. -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 -L/opt/alt/openssl/lib64 -L/opt/alt/ruby23/lib64 -Wl,-rpath=/opt/alt/openssl/lib64,-rpath=/opt/alt/ruby23/lib64 -fstack-protector -rdynamic -Wl,-export-dynamic  -m64   -Wl,-rpath,/opt/alt/ruby23/lib64 -L/opt/alt/ruby23/lib64 -lruby  -lpthread -ldl -lcrypt -lm   -lc"
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */

"gcc -o conftest -I/opt/alt/ruby23/include/ruby-2.3.0/x86_64-linux -I/opt/alt/ruby23/include/ruby-2.3.0/ruby/backward -I/opt/alt/ruby23/include/ruby-2.3.0 -I.    -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 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection conftest.c  -L. -L/opt/alt/ruby23/lib64 -Wl,-rpath,/opt/alt/ruby23/lib64 -L. -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 -L/opt/alt/openssl/lib64 -L/opt/alt/ruby23/lib64 -Wl,-rpath=/opt/alt/openssl/lib64,-rpath=/opt/alt/ruby23/lib64 -fstack-protector -rdynamic -Wl,-export-dynamic  -m64   -Wl,-rpath,/opt/alt/ruby23/lib64 -L/opt/alt/ruby23/lib64 -lruby -lsocket  -lpthread -ldl -lcrypt -lm   -lc"
/usr/bin/ld: cannot find -lsocket
collect2: error: ld returned 1 exit status
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: /*top*/
 4: extern int t(void);
 5: int main(int argc, char **argv)
 6: {
 7:   if (argc > 1000000) {
 8:     printf("%p", &t);
 9:   }
10: 
11:   return 0;
12: }
13: int t(void) { void ((*volatile p)()); p = (void ((*)()))main; return !p; }
/* end */

"gcc -o conftest -I/opt/alt/ruby23/include/ruby-2.3.0/x86_64-linux -I/opt/alt/ruby23/include/ruby-2.3.0/ruby/backward -I/opt/alt/ruby23/include/ruby-2.3.0 -I.    -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 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection conftest.c  -L. -L/opt/alt/ruby23/lib64 -Wl,-rpath,/opt/alt/ruby23/lib64 -L. -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 -L/opt/alt/openssl/lib64 -L/opt/alt/ruby23/lib64 -Wl,-rpath=/opt/alt/openssl/lib64,-rpath=/opt/alt/ruby23/lib64 -fstack-protector -rdynamic -Wl,-export-dynamic  -m64   -Wl,-rpath,/opt/alt/ruby23/lib64 -L/opt/alt/ruby23/lib64 -lruby -lsocket  -lpthread -ldl -lcrypt -lm   -lc"
conftest.c:13:13: error: conflicting types for 'main'
 extern void main();
             ^~~~
conftest.c:5:5: note: previous definition of 'main' was here
 int main(int argc, char **argv)
     ^~~~
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: /*top*/
 4: extern int t(void);
 5: int main(int argc, char **argv)
 6: {
 7:   if (argc > 1000000) {
 8:     printf("%p", &t);
 9:   }
10: 
11:   return 0;
12: }
13: extern void main();
14: int t(void) { main(); return 0; }
/* end */

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