"pkg-config --exists libffi"
package configuration for libffi is not found
"gcc -o conftest -I/opt/td-agent/embedded/include/ruby-2.4.0/x86_64-linux -I/opt/td-agent/embedded/include/ruby-2.4.0/ruby/backward -I/opt/td-agent/embedded/include/ruby-2.4.0 -I. -I/opt/td-agent/embedded/include -O2 -O3 -g -pipe -I/opt/td-agent/embedded/include   -I/opt/td-agent/embedded/include -O2 -O3 -g -pipe -fPIC conftest.c  -L. -L/opt/td-agent/embedded/lib -Wl,-rpath,/opt/td-agent/embedded/lib -L/opt/td-agent/embedded/lib -Wl,-rpath,/opt/td-agent/embedded/lib -L. -Wl,-rpath,/opt/td-agent/embedded/lib -L/opt/td-agent/embedded/lib -fstack-protector -rdynamic -Wl,-export-dynamic -L/opt/td-agent/embedded/lib  -Wl,-rpath,/opt/td-agent/embedded/lib     -Wl,-rpath,/opt/td-agent/embedded/lib -L/opt/td-agent/embedded/lib -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 */

/opt/td-agent/embedded/lib/ruby/gems/2.4.0/extensions/x86_64-linux/2.4.0/ffi-1.9.25/mkmf.log (END)