This is a HACK here; see comment in COptJumps.lh.
\begin{code}
-#if alpha_dec_osf1_TARGET && defined(__STG_TAILJUMPS__) && defined(__GNUC__)
+#if alpha_TARGET_ARCH && defined(__STG_TAILJUMPS__) && defined(__GNUC__)
register void *_procedure __asm__("$27");
#endif
#if (mipsel_TARGET_ARCH || mipseb_TARGET_ARCH) && defined(__STG_TAILJUMPS__) && defined(__GNUC__)