[libstdc++] [testsuite] xfail dbl from_chars for aarch64 rtems ldbl

[Alexandre Oliva <oliva@adacore.com>]

rtems, like vxworks, uses fast-float doubles for from_chars even for
long double, so it loses precision, so expect the long double bits to
fail on aarch64.

Regstrapped on x86_64-linux-gnu, also tested on aarch64-rtems6.  Ok to
install?


for  libstdc++-v3/ChangeLog

	* testsuite/20_util/from_chars/4.cc: Skip long double on
	aarch64-rtems.
---
 libstdc++-v3/testsuite/20_util/from_chars/4.cc |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/testsuite/20_util/from_chars/4.cc b/libstdc++-v3/testsuite/20_util/from_chars/4.cc
index 206e18daeb229..76e07df9d2bf3 100644
--- a/libstdc++-v3/testsuite/20_util/from_chars/4.cc
+++ b/libstdc++-v3/testsuite/20_util/from_chars/4.cc
@@ -18,7 +18,7 @@
 // <charconv> is supported in C++14 as a GNU extension
 // { dg-do run { target c++14 } }
 // { dg-add-options ieee }
-// { dg-additional-options "-DSKIP_LONG_DOUBLE" { target aarch64-*-vxworks* x86_64-*-vxworks* } }
+// { dg-additional-options "-DSKIP_LONG_DOUBLE" { target aarch64-*-rtems* aarch64-*-vxworks* x86_64-*-vxworks* } }
 
 #include <charconv>
 #include <string>

-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
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