dlfcn: Cleanups after -ldl is no longer required

This commit removes the ELF constructor and internal variables from
dlfcn/dlfcn.c.  The file now serves the same purpose as
nptl/libpthread-compat.c, so it is renamed to dlfcn/libdl-compat.c.
The use of libdl-shared-only-routines ensures that libdl.a is empty.

This commit adjusts the test suite not to use $(libdl).  The libdl.so
symbolic link is no longer installed.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/dlfcn/libdl-compat.c b/dlfcn/libdl-compat.c
new file mode 100644
index 0000000000..d197a98e79
--- /dev/null
+++ b/dlfcn/libdl-compat.c
@@ -0,0 +1,50 @@
+/* Placeholder compatibility symbols.
+   Copyright (C) 2005-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dlfcn.h>
+#include <shlib-compat.h>
+
+/* This file is used to keep specific symbol versions occupied, so
+   that ld does not generate weak symbol version definitions.  */
+
+void
+attribute_compat_text_section
+__attribute_used__
+__libdl_version_placeholder_1 (void)
+{
+}
+
+#if SHLIB_COMPAT (libdl, GLIBC_2_0, GLIBC_2_34)
+compat_symbol (libdl, __libdl_version_placeholder_1,
+               __libdl_version_placeholder, GLIBC_2_0);
+#endif
+
+#if SHLIB_COMPAT (libdl, GLIBC_2_1, GLIBC_2_34)
+compat_symbol (libdl, __libdl_version_placeholder_1,
+               __libdl_version_placeholder, GLIBC_2_1);
+#endif
+
+#if SHLIB_COMPAT (libdl, GLIBC_2_3_3, GLIBC_2_34)
+compat_symbol (libdl, __libdl_version_placeholder_1,
+               __libdl_version_placeholder, GLIBC_2_3_3);
+#endif
+
+#if SHLIB_COMPAT (libdl, GLIBC_2_3_4, GLIBC_2_34)
+compat_symbol (libdl, __libdl_version_placeholder_1,
+               __libdl_version_placeholder, GLIBC_2_3_4);
+#endif