dev-util/systemtap: cover mainloop.c as well, bug #510134

Bug: https://bugs.gentoo.org/510134
Package-Manager: Portage-2.3.13, Repoman-2.3.4

dev-util/systemtap/files/systemtap-3.1-ia64.patch

@@ -6,8 +6,6 @@ for PROBE2 macro.
 
 Reported-by: Émeric Maschino
 Bug: https://bugs.gentoo.org/510134
-diff --git a/cache.cxx b/cache.cxx
-index 3546b30..2710abf 100644
 --- a/cache.cxx
 +++ b/cache.cxx
 @@ -8,2 +8,10 @@
@@ -21,3 +19,15 @@ index 3546b30..2710abf 100644
 +#endif
 +
  #include "config.h"
+--- a/staprun/mainloop.c
++++ b/staprun/mainloop.c
+@@ -1 +1,9 @@
++#ifdef __ia64__
++// Default is: nor
++// We disable 'o' because gcc fails to select register
++// constraint for second instruction in 'add_script_to_cache'
++//     https://bugs.gentoo.org/510134
++#    define STAP_SDT_ARG_CONSTRAINT nr
++#endif
++
+ /* -*- linux-c -*-