[PATCH] better long double check

[PATCH] better long double check

[Szabolcs Nagy]

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s390x gcc default long double (64bit) does not
match the expected one in musl (128bit) but this
was not caught by the current configure check.

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From 94666565318b7ed966d77811e5d880f69bdecccf Mon Sep 17 00:00:00 2001
From: Szabolcs Nagy <nsz@port70.net>
Date: Sun, 17 Sep 2017 15:35:55 +0000
Subject: [PATCH] better configure check for long double support

---
 configure | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/configure b/configure
index 02b736ce..501a7219 100755
--- a/configure
+++ b/configure
@@ -706,9 +706,8 @@ esac
 #
 printf "checking whether compiler's long double definition matches float.h... "
 echo '#include <float.h>' > "$tmpc"
-echo '#if LDBL_MANT_DIG == 53' >> "$tmpc"
-echo 'typedef char ldcheck[9-(int)sizeof(long double)];' >> "$tmpc"
-echo '#endif' >> "$tmpc"
+echo '#define C(m,s) (m==LDBL_MANT_DIG && s==sizeof(long double))' >> "$tmpc"
+echo 'typedef char ldcheck[(C(53,8)||C(64,12)||C(64,16)||C(113,16))*2-1];' >> "$tmpc"
 if $CC $CFLAGS_C99FSE \
   -I$srcdir/arch/$ARCH -I$srcdir/arch/generic -I$srcdir/include \
   $CPPFLAGS $CFLAGS -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
-- 
2.14.1