+# On AIX, clog is present in libm as __clog
+AC_CHECK_LIB([m],[__clog],[AC_DEFINE([HAVE_CLOG],[1],[libm includes clog])])
+
+# Check for a isfinite macro that works on long doubles.
+LIBGFOR_CHECK_FOR_BROKEN_ISFINITE
+
+# Check for a isnan macro that works on long doubles.
+LIBGFOR_CHECK_FOR_BROKEN_ISNAN
+
+# Check for a fpclassify macro that works on long doubles.
+LIBGFOR_CHECK_FOR_BROKEN_FPCLASSIFY
+
+# Check whether the system has a working stat()
+LIBGFOR_CHECK_WORKING_STAT
+
+# Check whether __mingw_snprintf() is present
+LIBGFOR_CHECK_MINGW_SNPRINTF
+
+# Check for a broken powf implementation
+LIBGFOR_CHECK_FOR_BROKEN_POWF
+
+# Check for GNU libc feenableexcept
+AC_CHECK_LIB([m],[feenableexcept],[have_feenableexcept=yes AC_DEFINE([HAVE_FEENABLEEXCEPT],[1],[libm includes feenableexcept])])
+
+# Check for SysV fpsetmask
+LIBGFOR_CHECK_FPSETMASK
+
+# Check for AIX fp_trap and fp_enable
+AC_CHECK_FUNC([fp_trap],[have_fp_trap=yes AC_DEFINE([HAVE_FP_TRAP],[1],[fp_trap is present])])
+AC_CHECK_FUNC([fp_enable],[have_fp_enable=yes AC_DEFINE([HAVE_FP_ENABLE],[1],[fp_enable is present])])
+
+# Runs configure.host to set up necessary host-dependent shell variables.
+# We then display a message about it, and propagate them through the
+# build chain.
+. ${srcdir}/configure.host
+AC_MSG_NOTICE([FPU dependent file will be ${fpu_host}.h])
+FPU_HOST_HEADER=config/${fpu_host}.h
+AC_SUBST(FPU_HOST_HEADER)
+
+# Some targets require additional compiler options for IEEE compatibility.
+IEEE_FLAGS="${ieee_flags}"
+AC_SUBST(IEEE_FLAGS)
+
+# Check out attribute support.
+LIBGFOR_CHECK_ATTRIBUTE_VISIBILITY
+LIBGFOR_CHECK_ATTRIBUTE_DLLEXPORT
+LIBGFOR_CHECK_ATTRIBUTE_ALIAS
+
+# Check out sync builtins support.
+LIBGFOR_CHECK_SYNC_FETCH_AND_ADD
+
+# Check out thread support.
+LIBGFOR_CHECK_GTHR_DEFAULT
+
+# Check out #pragma weak.
+LIBGFOR_GTHREAD_WEAK