From 44c4e5d598bfcbb309f05ceb7a57ab02662e7f34 Mon Sep 17 00:00:00 2001
From: Roland McGrath <roland@hack.frob.com>
Date: Thu, 13 Mar 2014 10:38:27 -0700
Subject: Use __ehdr_start, when available, for rtld to get its own headers.

---
 configure.ac | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'configure.ac')

diff --git a/configure.ac b/configure.ac
index f3dd87d912..59dbb5e1b2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2069,6 +2069,27 @@ if test $libc_cv_predef_stack_protector = yes; then
 fi
 AC_SUBST(libc_extra_cflags)
 
+AC_CACHE_CHECK([whether the linker provides __ehdr_start],
+	       libc_cv_ehdr_start, [
+old_CFLAGS="$CFLAGS"
+old_LDFLAGS="$LDFLAGS"
+old_LIBS="$LIBS"
+CFLAGS="$CFLAGS -fPIC"
+LDFLAGS="$LDFLAGS -nostdlib -nostartfiles -shared"
+LIBS=
+AC_LINK_IFELSE([AC_LANG_SOURCE([
+extern const char __ehdr_start __attribute__ ((visibility ("hidden")));
+const char *ehdr (void) { return &__ehdr_start; }
+])],
+	       [libc_cv_ehdr_start=yes], [libc_cv_ehdr_start=no])
+CFLAGS="$old_CFLAGS"
+LDFLAGS="$old_LDFLAGS"
+LIBS="$old_LIBS"
+])
+if test $libc_cv_ehdr_start = yes; then
+  AC_DEFINE([HAVE_EHDR_START])
+fi
+
 ### End of automated tests.
 ### Now run sysdeps configure fragments.
 
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