Issue #11888: Use system log2() when available
I expect the system libc to use more accurate functions than Python. The GNU
libc uses for example FYL2X and FYL2XP1 hardware instructions on Intel FPU.
diff --git a/configure b/configure
index da4c902..6d3f85e 100755
--- a/configure
+++ b/configure
@@ -11864,7 +11864,7 @@
fi
done
-for ac_func in hypot lgamma log1p round tgamma
+for ac_func in hypot lgamma log1p log2 round tgamma
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"