With this we may finally build Windows and "native" toolchains
if host tools are also GCC11 based. For example:
1. You build cross toolchain with all the recent components by CT-NG
2. You build cross-canadian toolchain for Windows or ARC, ARMm whatever board
See upstream bug report [1] for more details.
Basically when we do cross-canadian build with
use of the same GCC11 as a "host" compiler we're seeing
an error like that:
------------------->8-------------------
mingw-w64-cross/gcc/x86_64-w64-mingw32/libstdc++-v3/include/fenv.h:58:11: error: 'fenv_t' has not been declared in '::'
58 | using ::fenv_t;
------------------->8-------------------
This is a solution proposed by Yujie Yang in [2]
Note, though it's not the final fix merged upstream, that's just
an attempt to fix this by casual GCC users. There's a hope it
will be fixed anyways a bit later, maybe by the time of GCC 11.3...
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100017
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100017#c20
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
