+AC_HEADER_SYS_WAIT
+AC_FUNC_ALLOCA
+AC_CHECK_FUNCS(sbrk utimes setmode getc_unlocked strcoll)
+
+# Check whether fopen64 is available and whether _LARGEFILE64_SOURCE
+# needs to be defined for it
+AC_MSG_CHECKING([for fopen64])
+AC_CACHE_VAL(bu_cv_have_fopen64,
+[AC_TRY_LINK([#include <stdio.h>], [FILE *f = fopen64 ("/tmp/foo","r");],
+bu_cv_have_fopen64=yes,
+[saved_CPPFLAGS=$CPPFLAGS
+ CPPFLAGS="$CPPFLAGS -D_LARGEFILE64_SOURCE"
+ AC_TRY_LINK([#include <stdio.h>], [FILE *f = fopen64 ("/tmp/foo","r");],
+bu_cv_have_fopen64="need -D_LARGEFILE64_SOURCE",
+bu_cv_have_fopen64=no)
+ CPPFLAGS=$saved_CPPFLAGS])])
+AC_MSG_RESULT($bu_cv_have_fopen64)
+if test "$bu_cv_have_fopen64" != no; then
+ AC_DEFINE([HAVE_FOPEN64], 1,
+ [Is fopen64 available?])
+fi
+AC_MSG_CHECKING([for stat64])
+AC_CACHE_VAL(bu_cv_have_stat64,
+[AC_TRY_LINK([#include <sys/stat.h>], [struct stat64 st; stat64 ("/tmp/foo", &st);],
+bu_cv_have_stat64=yes,
+[saved_CPPFLAGS=$CPPFLAGS
+ CPPFLAGS="$CPPFLAGS -D_LARGEFILE64_SOURCE"
+ AC_TRY_LINK([#include <sys/stat.h>], [struct stat64 st; stat64 ("/tmp/foo", &st);],
+bu_cv_have_stat64="need -D_LARGEFILE64_SOURCE",
+bu_cv_have_stat64=no)
+ CPPFLAGS=$saved_CPPFLAGS])])
+AC_MSG_RESULT($bu_cv_have_stat64)
+if test "$bu_cv_have_stat64" != no; then
+ AC_DEFINE([HAVE_STAT64], 1,
+ [Is stat64 available?])
+fi
+if test "$bu_cv_have_fopen64" = "need -D_LARGEFILE64_SOURCE" \
+ || test "$bu_cv_have_stat64" = "need -D_LARGEFILE64_SOURCE"; then
+ AC_DEFINE([_LARGEFILE64_SOURCE], 1,
+ [Enable LFS])
+ CPPFLAGS="$CPPFLAGS -D_LARGEFILE64_SOURCE"
+fi
+
+# Some systems have frexp only in -lm, not in -lc.
+AC_SEARCH_LIBS(frexp, m)