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Diffstat (limited to 'm4/link.m4')
| -rw-r--r-- | m4/link.m4 | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/m4/link.m4 b/m4/link.m4 new file mode 100644 index 0000000..d06b4f2 --- /dev/null +++ b/m4/link.m4 @@ -0,0 +1,58 @@ +# link.m4 serial 10 +dnl Copyright (C) 2009-2018 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +AC_DEFUN([gl_FUNC_LINK], +[ + AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_CHECK_FUNCS_ONCE([link]) + if test $ac_cv_func_link = no; then + HAVE_LINK=0 + else + AC_CACHE_CHECK([whether link obeys POSIX], + [gl_cv_func_link_works], + [touch conftest.a + # Assume that if we have lstat, we can also check symlinks. + if test $ac_cv_func_lstat = yes; then + ln -s conftest.a conftest.lnk + fi + AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [[#include <unistd.h> + #include <stdio.h> + ]], + [[int result = 0; + if (!link ("conftest.a", "conftest.b/")) + result |= 1; +#if HAVE_LSTAT + if (!link ("conftest.lnk/", "conftest.b")) + result |= 2; + if (rename ("conftest.a", "conftest.b")) + result |= 4; + if (!link ("conftest.b", "conftest.lnk")) + result |= 8; +#endif + return result; + ]])], + [gl_cv_func_link_works=yes], [gl_cv_func_link_works=no], + [case "$host_os" in + # Guess yes on Linux systems. + linux-* | linux) gl_cv_func_link_works="guessing yes" ;; + # Guess yes on glibc systems. + *-gnu* | gnu*) gl_cv_func_link_works="guessing yes" ;; + # If we don't know, assume the worst. + *) gl_cv_func_link_works="guessing no" ;; + esac + ]) + rm -f conftest.a conftest.b conftest.lnk]) + case "$gl_cv_func_link_works" in + *yes) ;; + *) + REPLACE_LINK=1 + ;; + esac + fi +]) |