have_func('rb_thread_fd_select') returns false
Hello all. I don't know if this is a bug or an error on my part of setting something up.
I was unable to install the eventmachine gem against a version of ruby I compiled from trunk due to have_func('rb_thread_fd_select') reporting false when it should report true.
mkmf.rb seems to be generating commands to point to the right include directories:
clang -o conftest -I/usr/local/include/ruby-2.4.0/x86_64-darwin14 -I/usr/local/include/ruby-2.4.0/ruby/backward -I/usr/local/include/ruby-2.4.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -O0 -fno-fast-math -g -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -Wdivision-by-zero -Wdeprecated-declarations -Wextra-tokens -pipe conftest.c -L. -L/usr/local/lib -L. -fstack-protector -L/usr/local/lib -lruby-static -framework CoreFoundation -lpthread -lgmp -ldl -lobjc
Other have_func calls seems to work as expected. If I 'hack' eventmachine to assume it returns true, everything works as expected.
Could someone more experienced than I help me debug what's going on here? have_func('rb_thread_fd_select') should only correctly return false for ruby version < 1.9, of which I have none installed on my system, so something is failing here.