JezK
Edit File: mkmf.log
have_library: checking for clock_gettime() in -lrt... -------------------- yes "gcc -o conftest -I/usr/include/x86_64-linux-gnu/ruby-2.1.0 -I/usr/include/ruby-2.1.0/ruby/backward -I/usr/include/ruby-2.1.0 -I. -D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -fPIC conftest.c -L. -L/usr/lib/x86_64-linux-gnu -L. -Wl,-z,relro -L/build/ruby2.1-bDDI0O/ruby2.1-2.1.5/debian/lib -fstack-protector -rdynamic -Wl,-export-dynamic -lruby-2.1 -lpthread -lgmp -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/usr/include/x86_64-linux-gnu/ruby-2.1.0 -I/usr/include/ruby-2.1.0/ruby/backward -I/usr/include/ruby-2.1.0 -I. -D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -fPIC conftest.c -L. -L/usr/lib/x86_64-linux-gnu -L. -Wl,-z,relro -L/build/ruby2.1-bDDI0O/ruby2.1-2.1.5/debian/lib -fstack-protector -rdynamic -Wl,-export-dynamic -lruby-2.1 -lrt -lpthread -lgmp -ldl -lcrypt -lm -lc" conftest.c: In function 't': conftest.c:13:57: error: 'clock_gettime' undeclared (first use in this function) int t(void) { void ((*volatile p)()); p = (void ((*)()))clock_gettime; return 0; } ^ conftest.c:13:57: note: each undeclared identifier is reported only once for each function it appears in checked program was: /* begin */ 1: #include "ruby.h" 2: 3: /*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 ((*)()))clock_gettime; return 0; } /* end */ "gcc -o conftest -I/usr/include/x86_64-linux-gnu/ruby-2.1.0 -I/usr/include/ruby-2.1.0/ruby/backward -I/usr/include/ruby-2.1.0 -I. -D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -fPIC conftest.c -L. -L/usr/lib/x86_64-linux-gnu -L. -Wl,-z,relro -L/build/ruby2.1-bDDI0O/ruby2.1-2.1.5/debian/lib -fstack-protector -rdynamic -Wl,-export-dynamic -lruby-2.1 -lrt -lpthread -lgmp -ldl -lcrypt -lm -lc" 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) { clock_gettime(); return 0; } /* end */ --------------------