diff --git a/Rakefile b/Rakefile
index 604f80c..b3f0005 100644
--- a/Rakefile
+++ b/Rakefile
@@ -10,6 +10,10 @@ Rake::ExtensionTask.new('libpsem') do |ext|
   ext.lib_dir = 'lib/process_shared'
 end
 
+Rake::ExtensionTask.new('helper') do |ext|
+  ext.lib_dir = 'lib/process_shared/posix'
+end
+
 desc 'Run the tests'
 task :default => [:test]
 
@@ -22,3 +26,5 @@ Gem::PackageTask.new(gemspec) do |p|
   p.need_tar = true
   p.gem_spec = gemspec
 end
+
+task :gem => :compile
diff --git a/ext/helper/extconf.rb b/ext/helper/extconf.rb
new file mode 100644
index 0000000..7b78fa0
--- /dev/null
+++ b/ext/helper/extconf.rb
@@ -0,0 +1,14 @@
+require 'mkmf'
+
+have_header('fcntl.h')
+
+have_header('sys/mman.h')
+
+have_header('semaphore.h')
+have_type('sem_t', 'semaphore.h')
+
+have_header('pthread.h')
+have_type('pthread_mutex_t', 'pthread.h')
+have_type('pthread_mutexattr_t', 'pthread.h')
+
+create_makefile('helper')
diff --git a/ext/helper/helper.c b/ext/helper/helper.c
new file mode 100644
index 0000000..6436b98
--- /dev/null
+++ b/ext/helper/helper.c
@@ -0,0 +1,70 @@
+/****************************/
+/* File descriptor controls */
+/****************************/
+
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+extern int o_rdwr;
+int o_rdwr = O_RDWR;
+extern int o_creat;
+int o_creat = O_CREAT;
+extern int o_excl;
+int o_excl = O_EXCL;
+#endif
+
+/************************/
+/* Memory Map constants */
+/************************/
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+
+extern int prot_read;
+extern int prot_write;
+extern int prot_exec;
+extern int prot_none;
+
+extern void * map_failed;
+extern int map_shared;
+extern int map_private;
+
+int prot_read = PROT_READ;
+int prot_write = PROT_WRITE;
+int prot_exec = PROT_EXEC;
+int prot_none = PROT_NONE;
+
+void * map_failed = MAP_FAILED;
+int map_shared = MAP_SHARED;
+int map_private = MAP_PRIVATE;
+#endif
+
+/****************************************/
+/* PThread and related types and macros */
+/****************************************/
+
+#ifdef HAVE_PTHREAD_H
+#include <pthread.h>
+extern int pthread_process_shared;
+int pthread_process_shared = PTHREAD_PROCESS_SHARED;
+#endif
+
+#ifdef HAVE_TYPE_PTHREAD_MUTEX_T
+extern size_t sizeof_pthread_mutex_t;
+size_t sizeof_pthread_mutex_t = sizeof (pthread_mutex_t);
+size_t sizeof_pthread_mutexattr_t = sizeof (pthread_mutexattr_t);
+#endif
+
+#ifdef HAVE_TYPE_PTHREAD_MUTEXATTR_T
+extern size_t sizeof_pthread_mutexattr_t;
+#endif
+
+/******************/
+/* Semaphore type */
+/******************/
+
+#ifdef HAVE_TYPE_SEM_T
+#include <semaphore.h>
+extern size_t sizeof_sem_t;
+size_t sizeof_sem_t = sizeof (sem_t);
+#endif
+