+ unset|*yes)
+ AC_CACHE_CHECK([whether perror matches strerror],
+ [gl_cv_func_perror_works],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <errno.h>
+ #include <stdio.h>
+ ]],
+ [[char *str = strerror (-1);
+ if (!getenv("CONFTEST_OUTPUT")) return 0;
+ if (!str) str = "";
+ puts (str);
+ errno = -1;
+ perror ("");
+ ]])],
+ [CONFTEST_OUTPUT=1 ./conftest$EXEEXT >conftest.txt1 2>conftest.txt2
+ if cmp conftest.txt1 conftest.txt2 >/dev/null; then
+ gl_cv_func_perror_works=yes
+ else
+ gl_cv_func_perror_works=no
+ fi
+ rm -rf conftest.txt1 conftest.txt2],
+ [gl_cv_func_perror_works=no],
+ [dnl Guess no when cross-compiling.
+ gl_cv_func_perror_works="guessing no"])])
+ if test "$gl_cv_func_perror_works" != yes; then
+ REPLACE_PERROR=1
+ fi ;;