I'm seeing this wrong guess on a glibc system: checking whether ungetc works on arbitrary bytes... guessing no
2012-05-05 Bruno Haible <br...@clisp.org> fseeko-tests, ftello-tests: Avoid "guessing no" when cross-compiling. * m4/ungetc.m4 (gl_FUNC_UNGETC_WORKS): Require AC_CANONICAL_HOST. When cross-compiling to a glibc platform, set gl_cv_func_ungetc_works to "guessing yes". --- m4/ungetc.m4.orig Sat May 5 11:46:51 2012 +++ m4/ungetc.m4 Sat May 5 08:51:16 2012 @@ -1,4 +1,4 @@ -# ungetc.m4 serial 2 +# ungetc.m4 serial 3 dnl Copyright (C) 2009-2012 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -7,6 +7,7 @@ AC_DEFUN_ONCE([gl_FUNC_UNGETC_WORKS], [ AC_REQUIRE([AC_PROG_CC]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CACHE_CHECK([whether ungetc works on arbitrary bytes], [gl_cv_func_ungetc_works], @@ -27,10 +28,19 @@ if (fgetc (f) != 'c') return 11; fclose (f); remove ("conftest.tmp");])], [gl_cv_func_ungetc_works=yes], [gl_cv_func_ungetc_works=no], - [gl_cv_func_ungetc_works='guessing no']) + [case "$host_os" in + # Guess yes on glibc systems. + *-gnu*) gl_cv_func_ungetc_works="guessing yes" ;; + # If we don't know, assume the worst. + *) gl_cv_func_ungetc_works="guessing no" ;; + esac + ]) ]) - if test "$gl_cv_func_ungetc_works" != yes; then - AC_DEFINE([FUNC_UNGETC_BROKEN], [1], - [Define to 1 if ungetc is broken when used on arbitrary bytes.]) - fi + case "$gl_cv_func_ungetc_works" in + *yes) ;; + *) + AC_DEFINE([FUNC_UNGETC_BROKEN], [1], + [Define to 1 if ungetc is broken when used on arbitrary bytes.]) + ;; + esac ])