+ m4_ifdef([gl_FUNC_CBRTL_IEEE], [
+ if test $gl_cbrtl_required = ieee && test $REPLACE_CBRTL = 0; then
+ AC_CACHE_CHECK([whether cbrtl works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_cbrtl_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $CBRTL_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+static long double dummy (long double x) { return 0; }
+int main (int argc, char *argv[])
+{
+ extern
+ #ifdef __cplusplus
+ "C"
+ #endif
+ long double cbrtl (long double);
+ long double (*my_cbrtl) (long double) = argc ? cbrtl : dummy;
+ long double f;
+ /* Test cbrtl(-0.0).
+ This test fails on IRIX 6.5. */
+ f = my_cbrtl (minus_zerol);
+ if (!(f == 0.0L) || (signbitl (minus_zerol) && !signbitl (f)))
+ return 1;
+ return 0;
+}
+ ]])],
+ [gl_cv_func_cbrtl_ieee=yes],
+ [gl_cv_func_cbrtl_ieee=no],
+ [gl_cv_func_cbrtl_ieee="guessing no"])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_cbrtl_ieee" in
+ *yes) ;;
+ *) REPLACE_CBRTL=1 ;;
+ esac
+ fi
+ ])