+# For the streamoff typedef.
+GLIBCXX_CHECK_INT64_T
+
+# For LFS support.
+GLIBCXX_CHECK_LFS
+
+# For showmanyc_helper().
+AC_CHECK_HEADERS(sys/ioctl.h sys/filio.h)
+GLIBCXX_CHECK_POLL
+GLIBCXX_CHECK_S_ISREG_OR_S_IFREG
+
+# For xsputn_2().
+AC_CHECK_HEADERS(sys/uio.h)
+GLIBCXX_CHECK_WRITEV
+
+# For C99 support to TR1.
+GLIBCXX_CHECK_C99_TR1
+
+# For common values of EOF, SEEK_CUR, SEEK_END.
+GLIBCXX_CHECK_STDIO_MACROS
+
+# For gettimeofday support.
+GLIBCXX_CHECK_GETTIMEOFDAY
+
+# For clock_gettime support.
+# NB: The default is [no], because otherwise it requires linking.
+GLIBCXX_ENABLE_CLOCK_GETTIME([no])
+
+# For gthread support
+GLIBCXX_CHECK_GTHREADS
+
+# For nanosleep support
+GLIBCXX_CHECK_NANOSLEEP
+
+AC_LC_MESSAGES
+
+# Check for available headers.
+AC_CHECK_HEADERS([endian.h float.h fp.h ieeefp.h inttypes.h locale.h \
+machine/endian.h machine/param.h nan.h stdint.h stdlib.h string.h \
+strings.h sys/ipc.h sys/isa_defs.h sys/machine.h sys/param.h \
+sys/resource.h sys/sem.h sys/stat.h sys/time.h sys/types.h unistd.h \
+wchar.h wctype.h])