fesetexceptflag(): Set FE_ALL_INVALID instead of FE_ALL_EXCEPT for
FE_INVALID. Taken from FreeBSD:

https://cgit.freebsd.org/src/commit/lib/msun/powerpc/fenv.h?id=e7bd4f846f0c9185aebfd3d116bb78ab137280fa

> [POWERPC] msun: fix incorrect flag in fesetexceptflag
> Fix incorrect mask being used when FE_INVALID bit is wanted by user.
> The problem was noticed thanks to msun fenv tests.
>
> Reviewed by: jhibbits, luporl
> Sponsored by: Eldorado Research Institute (eldorado.org.br)
> Differential Revision: https://reviews.freebsd.org/D27201

No regression for full ATF on both real and emulated FPU.

XXX
Import some tests from FreeBSD's lib/msun/tests.

do the ignore builtin dance for gcc-8

branches: 1.5.2;
s/static inline/static __inline/g for consistency.

branches: 1.4.2; 1.4.4;
Fixed feholdexcept() by copying the actual contents of FPSCR to the fenv_t
instead of a double precision floating point representation of it.

branches: 1.3.6;
provide a common softfloat fenv implemenation and use it for softfloat builds.
restore ABI compatibility with previous releases for ieeefp.h on sh3.
add namespace.h protection for all the fenv interfaces.
use MKSOFTFLOAT on sh3 instead of assuming softfloat.
standardize on comparing MKSOFTFLOAT with "no".
remove the arm-specific softfloat fenv code (which also had several bugs).
fix logic errors in the arm hardfloat feraiseexcept() and feupdateenv().

update the FE0/FE1 MSR bits as needed when changing the exception mask.

branches: 1.1.2; 1.1.4; 1.1.6;
Add fenv.h for powerpc (from FreeBSD)

do the ignore builtin dance for gcc-8

s/static inline/static __inline/g for consistency.

branches: 1.4.2; 1.4.4;
Fixed feholdexcept() by copying the actual contents of FPSCR to the fenv_t
instead of a double precision floating point representation of it.

branches: 1.3.6;
provide a common softfloat fenv implemenation and use it for softfloat builds.
restore ABI compatibility with previous releases for ieeefp.h on sh3.
add namespace.h protection for all the fenv interfaces.
use MKSOFTFLOAT on sh3 instead of assuming softfloat.
standardize on comparing MKSOFTFLOAT with "no".
remove the arm-specific softfloat fenv code (which also had several bugs).
fix logic errors in the arm hardfloat feraiseexcept() and feupdateenv().

update the FE0/FE1 MSR bits as needed when changing the exception mask.

branches: 1.1.2; 1.1.4; 1.1.6;
Add fenv.h for powerpc (from FreeBSD)

s/static inline/static __inline/g for consistency.

branches: 1.4.2; 1.4.4;
Fixed feholdexcept() by copying the actual contents of FPSCR to the fenv_t
instead of a double precision floating point representation of it.

branches: 1.3.6;
provide a common softfloat fenv implemenation and use it for softfloat builds.
restore ABI compatibility with previous releases for ieeefp.h on sh3.
add namespace.h protection for all the fenv interfaces.
use MKSOFTFLOAT on sh3 instead of assuming softfloat.
standardize on comparing MKSOFTFLOAT with "no".
remove the arm-specific softfloat fenv code (which also had several bugs).
fix logic errors in the arm hardfloat feraiseexcept() and feupdateenv().

update the FE0/FE1 MSR bits as needed when changing the exception mask.

branches: 1.1.2; 1.1.4; 1.1.6;
Add fenv.h for powerpc (from FreeBSD)

Fixed feholdexcept() by copying the actual contents of FPSCR to the fenv_t
instead of a double precision floating point representation of it.

branches: 1.3.6;
provide a common softfloat fenv implemenation and use it for softfloat builds.
restore ABI compatibility with previous releases for ieeefp.h on sh3.
add namespace.h protection for all the fenv interfaces.
use MKSOFTFLOAT on sh3 instead of assuming softfloat.
standardize on comparing MKSOFTFLOAT with "no".
remove the arm-specific softfloat fenv code (which also had several bugs).
fix logic errors in the arm hardfloat feraiseexcept() and feupdateenv().

update the FE0/FE1 MSR bits as needed when changing the exception mask.

branches: 1.1.2; 1.1.4; 1.1.6;
Add fenv.h for powerpc (from FreeBSD)

provide a common softfloat fenv implemenation and use it for softfloat builds.
restore ABI compatibility with previous releases for ieeefp.h on sh3.
add namespace.h protection for all the fenv interfaces.
use MKSOFTFLOAT on sh3 instead of assuming softfloat.
standardize on comparing MKSOFTFLOAT with "no".
remove the arm-specific softfloat fenv code (which also had several bugs).
fix logic errors in the arm hardfloat feraiseexcept() and feupdateenv().

update the FE0/FE1 MSR bits as needed when changing the exception mask.

branches: 1.1.2; 1.1.4; 1.1.6;
Add fenv.h for powerpc (from FreeBSD)

update the FE0/FE1 MSR bits as needed when changing the exception mask.

branches: 1.1.2;
Add fenv.h for powerpc (from FreeBSD)

branches: 1.1.2;
Add fenv.h for powerpc (from FreeBSD)