+ dnl The system's strerror() has a wrong signature.
+ dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.
+ AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])
+ dnl In glibc < 2.14, __xpg_strerror_r does not populate buf on failure.
+ dnl In cygwin < 1.7.10, __xpg_strerror_r clobbers strerror's buffer.
+ if test $ac_cv_func___xpg_strerror_r = yes; then
+ AC_CACHE_CHECK([whether __xpg_strerror_r works],
+ [gl_cv_func_strerror_r_works],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <errno.h>
+ #include <string.h>
+ extern
+ #ifdef __cplusplus
+ "C"
+ #endif
+ int __xpg_strerror_r(int, char *, size_t);
+ ]],
+ [[int result = 0;
+ char buf[256] = "^";
+ char copy[256];
+ char *str = strerror (-1);
+ strcpy (copy, str);
+ if (__xpg_strerror_r (-2, buf, 1) == 0)
+ result |= 1;
+ if (*buf)
+ result |= 2;
+ __xpg_strerror_r (-2, buf, 256);
+ if (strcmp (str, copy))
+ result |= 4;
+ return result;
+ ]])],
+ [gl_cv_func_strerror_r_works=yes],
+ [gl_cv_func_strerror_r_works=no],
+ [dnl Guess no on all platforms that have __xpg_strerror_r,
+ dnl at least until fixed glibc and cygwin are more common.
+ gl_cv_func_strerror_r_works="guessing no"
+ ])
+ ])
+ fi