- dnl Test whether fabsf() exists. Assume that fabsf(), if it exists, is
- dnl defined in the same library as fabs().
- save_LIBS="$LIBS"
- LIBS="$LIBS $FABS_LIBM"
- AC_CHECK_FUNCS([fabsf])
- LIBS="$save_LIBS"
- if test $ac_cv_func_fabsf = yes; then
- FABSF_LIBM="$FABS_LIBM"
- else
+ dnl Persuade glibc <math.h> to declare fabsf().
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+ dnl Test whether fabsf() exists. We cannot assume that fabsf(), if it
+ dnl exists, is defined in the same library as fabs(). This is not the case
+ dnl on FreeBSD, NetBSD, OpenBSD.
+ gl_MATHFUNC([fabsf], [float], [(float)])
+ if test $gl_cv_func_fabsf_no_libm = no \
+ && test $gl_cv_func_fabsf_in_libm = no; then