Revert "Fix HAVE_RM_CTX -Wundef warnings"

This reverts commit 9290130a8de3f30970f741c79dfe8459f798e05f.
Revert "Fix _IO_JUMPS_OFFSET -Wundef warnings"

This reverts commit f7efd7c3dfffa3c417e9d3c4cb19d9954a3b1421.
Revert "Fix HP_SMALL_TIMING_AVAIL -Wundef warnings"

This reverts commit 53f1bed39263541ef7f3d86f9701005524938016.
Revert "Fix __PTHREAD_MUTEX_HAVE_ELISION -Wundef warning"

This reverts commit 788bba368c2eaf8aa3fd2ca18d269395d6bc8afb.