Add gnulib modules to replace missing libc functionality

This enables us to build a fully featured elfutils package on systems
with reduced C libraries, such as windows. All the modules are built
into libgnu.a, which is then linked into all binaries if
--enable-gnulib is given on the configure line.

Change-Id: I743fd22172bc85d9f10dcc3dad8eb921f462b554
Reviewed-by: Christian Kandeler <[email protected]>

1 files changed, 99 insertions, 0 deletions

diff --git a/m4/getline.m4 b/m4/getline.m4
new file mode 100644
index 00000000..dcea772e
--- /dev/null
+++ b/m4/getline.m4
@@ -0,0 +1,99 @@
+# getline.m4 serial 27
+
+dnl Copyright (C) 1998-2003, 2005-2007, 2009-2017 Free Software Foundation,
+dnl Inc.
+dnl
+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_PREREQ([2.59])
+
+dnl See if there's a working, system-supplied version of the getline function.
+dnl We can't just do AC_REPLACE_FUNCS([getline]) because some systems
+dnl have a function by that name in -linet that doesn't have anything
+dnl to do with the function we need.
+AC_DEFUN([gl_FUNC_GETLINE],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+
+  dnl Persuade glibc <stdio.h> to declare getline().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([getline])
+
+  gl_getline_needs_run_time_check=no
+  AC_CHECK_FUNC([getline],
+                [dnl Found it in some library.  Verify that it works.
+                 gl_getline_needs_run_time_check=yes],
+                [am_cv_func_working_getline=no])
+  if test $gl_getline_needs_run_time_check = yes; then
+    AC_CACHE_CHECK([for working getline function], [am_cv_func_working_getline],
+    [echo fooNbarN | tr -d '\012' | tr N '\012' > conftest.data
+    AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#    include <stdio.h>
+#    include <stdlib.h>
+#    include <string.h>
+    int main ()
+    {
+      FILE *in = fopen ("./conftest.data", "r");
+      if (!in)
+        return 1;
+      {
+        /* Test result for a NULL buffer and a zero size.
+           Based on a test program from Karl Heuer.  */
+        char *line = NULL;
+        size_t siz = 0;
+        int len = getline (&line, &siz, in);
+        if (!(len == 4 && line && strcmp (line, "foo\n") == 0))
+          return 2;
+        free (line);
+      }
+      {
+        /* Test result for a NULL buffer and a non-zero size.
+           This crashes on FreeBSD 8.0.  */
+        char *line = NULL;
+        size_t siz = (size_t)(~0) / 4;
+        if (getline (&line, &siz, in) == -1)
+          return 3;
+        free (line);
+      }
+      fclose (in);
+      return 0;
+    }
+    ]])], [am_cv_func_working_getline=yes] dnl The library version works.
+    , [am_cv_func_working_getline=no] dnl The library version does NOT work.
+    , dnl We're cross compiling. Assume it works on glibc2 systems.
+      [AC_EGREP_CPP([Lucky GNU user],
+         [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ >= 2) && !defined __UCLIBC__
+  Lucky GNU user
+ #endif
+#endif
+         ],
+         [am_cv_func_working_getline="guessing yes"],
+         [am_cv_func_working_getline="guessing no"])]
+    )])
+  fi
+
+  if test $ac_cv_have_decl_getline = no; then
+    HAVE_DECL_GETLINE=0
+  fi
+
+  case "$am_cv_func_working_getline" in
+    *no)
+      dnl Set REPLACE_GETLINE always: Even if we have not found the broken
+      dnl getline function among $LIBS, it may exist in libinet and the
+      dnl executable may be linked with -linet.
+      REPLACE_GETLINE=1
+      ;;
+  esac
+])
+
+# Prerequisites of lib/getline.c.
+AC_DEFUN([gl_PREREQ_GETLINE],
+[
+  :
+])