science/dakota: fix build on non-x86

fpinit.c uses fpsetmask to workaround a bug that is not present since
FreeBSD 4.0.

This issue also affected Firefox and was resolved 9 years ago
https://bugzilla.mozilla.org/show_bug.cgi?id=789436

science/dakota/files/patch-packages_external_ampl_fpinit.c

@@ -0,0 +1,11 @@
+--- packages/external/ampl/fpinit.c.orig	2021-10-21 13:10:57 UTC
++++ packages/external/ampl/fpinit.c
+@@ -214,7 +214,7 @@ fpinit_ASL(Void)
+ 
+ /* Currently, FP_PD is the default on FreeBSD, but enabled traps */
+ /* can cause surprises, so we restore the default IEEE mask. */
+-#ifdef __FreeBSD__
++#if defined(__FreeBSD__) && (defined (__amd64__) || defined(__i386__))
+ #include "floatingpoint.h"
+ #define FP_INIT_DONE
+  void