math: fix fma bug on x86 (found by Bruno Haible with gnulib)

[musl] / configure

diff --git a/configure b/configure
index d29d2dc..7e5a8df 100755 (executable)
--- a/configure
+++ b/configure
@@ -70,7 +70,7 @@ fi
 tryldflag () {
 printf "checking whether linker accepts %s... " "$2"
 echo "typedef int x;" > "$tmpc"
-if "$CC" -shared "$2" -o /dev/null "$tmpc" 2>/dev/null ; then
+if "$CC" -nostdlib -shared "$2" -o /dev/null "$tmpc" 2>/dev/null ; then
 printf "yes\n"
 eval "$1=\"\${$1} \$2\""
 eval "$1=\${$1# }"
@@ -267,6 +267,13 @@ fi
 tryflag CFLAGS_AUTO -fno-stack-protector
 tryldflag LDFLAGS_AUTO -Wl,--hash-style=sysv
 
+# Disable dynamic linking if ld is broken and can't do -Bsymbolic-functions
+LDFLAGS_DUMMY=
+tryldflag LDFLAGS_DUMMY -Wl,-Bsymbolic-functions || {
+printf "warning: disabling dynamic linking support\n"
+shared=no
+}
+
 
 printf "creating config.mak... "