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

"gcc -o conftest -I/opt/alt/ruby19/include/ruby-1.9.1/x86_64-linux -I/opt/alt/ruby19/include/ruby-1.9.1/ruby/backward -I/opt/alt/ruby19/include/ruby-1.9.1 -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/ruby19/lib64 -Wl,-R/opt/alt/ruby19/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/ruby19/lib64 -Wl,-rpath=/opt/alt/openssl/lib64,-rpath=/opt/alt/ruby19/lib64 -rdynamic -Wl,-export-dynamic  -m64   -Wl,-R -Wl,/opt/alt/ruby19/lib64 -L/opt/alt/ruby19/lib64 -lruby  -lpthread -lrt -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/ruby19/include/ruby-1.9.1/x86_64-linux -I/opt/alt/ruby19/include/ruby-1.9.1/ruby/backward -I/opt/alt/ruby19/include/ruby-1.9.1 -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/ruby19/lib64 -Wl,-R/opt/alt/ruby19/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/ruby19/lib64 -Wl,-rpath=/opt/alt/openssl/lib64,-rpath=/opt/alt/ruby19/lib64 -rdynamic -Wl,-export-dynamic  -m64   -Wl,-R -Wl,/opt/alt/ruby19/lib64 -L/opt/alt/ruby19/lib64 -lruby -lsocket  -lpthread -lrt -ldl -lcrypt -lm   -lc"
conftest.c: In function 't':
conftest.c:4:53: error: 'main' undeclared (first use in this function)
 int t() { void ((*volatile p)()); p = (void ((*)()))main; return 0; }
                                                     ^~~~
conftest.c:4:53: note: each undeclared identifier is reported only once for each function it appears in
conftest.c:4:28: warning: variable 'p' set but not used [-Wunused-but-set-variable]
 int t() { void ((*volatile p)()); p = (void ((*)()))main; return 0; }
                            ^
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: /*top*/
 4: int t() { void ((*volatile p)()); p = (void ((*)()))main; return 0; }
 5: int main(int argc, char **argv)
 6: {
 7:   if (argc > 1000000) {
 8:     printf("%p", &t);
 9:   }
10: 
11:   return 0;
12: }
/* end */

"gcc -o conftest -I/opt/alt/ruby19/include/ruby-1.9.1/x86_64-linux -I/opt/alt/ruby19/include/ruby-1.9.1/ruby/backward -I/opt/alt/ruby19/include/ruby-1.9.1 -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/ruby19/lib64 -Wl,-R/opt/alt/ruby19/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/ruby19/lib64 -Wl,-rpath=/opt/alt/openssl/lib64,-rpath=/opt/alt/ruby19/lib64 -rdynamic -Wl,-export-dynamic  -m64   -Wl,-R -Wl,/opt/alt/ruby19/lib64 -L/opt/alt/ruby19/lib64 -lruby -lsocket  -lpthread -lrt -ldl -lcrypt -lm   -lc"
conftest.c: In function 't':
conftest.c:4:11: warning: implicit declaration of function 'main' [-Wimplicit-function-declaration]
 int t() { main(); return 0; }
           ^~~~
/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: int t() { main(); return 0; }
 5: int main(int argc, char **argv)
 6: {
 7:   if (argc > 1000000) {
 8:     printf("%p", &t);
 9:   }
10: 
11:   return 0;
12: }
/* end */

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