diff -up ilmbase-1.0.3/IexMath/IexMathFpu.cpp.secondary ilmbase-1.0.3/IexMath/IexMathFpu.cpp
--- ilmbase-1.0.3/IexMath/IexMathFpu.cpp.secondary	2012-09-04 10:26:55.000000000 +0200
+++ ilmbase-1.0.3/IexMath/IexMathFpu.cpp	2012-09-04 10:27:20.000000000 +0200
@@ -27,7 +27,7 @@
 #endif
 
 
-#ifdef HAVE_UCONTEXT_H
+#if defined(HAVE_UCONTEXT_H) && (defined(__x86_64__) || defined(__i386__))
 
 
 #include <ucontext.h>