Make sure that the same tests are on all platforms.

In order to be able to generate a list of tests for cts, the same set of
tests must exist across all platforms. This CL adds empty tests where a
test was conditionally compiled out.

This CL creates a single library libBionicTests that includes all of
the tests found in bionic-unit-tests-static.

Also fix a few missing include files in some test files.

Tested by running and compiling the tests for every platform and
verifying the same number of tests are on each platform.

Change-Id: I9989d4bfebb0f9c409a0ce7e87169299eac605a2
diff --git a/tests/eventfd_test.cpp b/tests/eventfd_test.cpp
index 2c2c5f0..aa88a3b 100644
--- a/tests/eventfd_test.cpp
+++ b/tests/eventfd_test.cpp
@@ -14,11 +14,25 @@
  * limitations under the License.
  */
 
+#include <errno.h>
+#include <fcntl.h>
+
 #include <gtest/gtest.h>
 
-#if !defined(__GLIBC__) // Android's prebuilt gcc's header files don't include <sys/eventfd.h>.
-
+#if defined(__BIONIC__) // Android's prebuilt gcc's header files don't include <sys/eventfd.h>.
 #include <sys/eventfd.h>
+#else
+// Include the necessary components of sys/eventfd.h right here.
+#include <stdint.h>
+
+typedef uint64_t eventfd_t;
+
+__BEGIN_DECLS
+extern int eventfd(int, int);
+extern int eventfd_read(int, eventfd_t*);
+extern int eventfd_write(int, eventfd_t);
+__END_DECLS
+#endif
 
 TEST(eventfd, smoke) {
   unsigned int initial_value = 2;
@@ -43,5 +57,3 @@
 
   close(fd);
 }
-
-#endif