Cactus Code Thorn NaNCatcher
Authors    : Erik Schnetter <schnetter@uni-tuebingen.de>
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Purpose of the thorn:

Switch the FPU into a mode where it catches nans and infinities.
Whether this is possible, andor whether this code knows how to do
that, is hardware and operating system dependent.



This should work on the following systems:

Systems with a GNU C library (glibc), version 2.2 or later, using
<fenv.h>.

Linux systems with an IA32 (aka i386) processor, when the compiler is
GNU or Intel, using <fpu_control.h>.

PowerPC systems with a GNU compiler, using code taken from the GNU C
library.

In cases where the nan-catcher does not work, you will see a warning
message "NaNCatcher disabled -- no support for your compiler" early at
run time.
