Add crt1-2.0.o for glibc 2.0 compatibility tests

Starting from glibc 2.1, crt1.o contains _IO_stdin_used which is checked
by _IO_check_libio to provide binary compatibility for glibc 2.0.  Add
crt1-2.0.o for tests against glibc 2.0.  Define tests-2.0 for glibc 2.0
compatibility tests.  Add and update glibc 2.0 compatibility tests for
stderr, matherr and pthread_kill.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Makeconfig

@@ -360,6 +360,8 @@ whole-archive = -Wl,--whole-archive
 # Installed name of the startup code.
 # The ELF convention is that the startfile is called crt1.o
 start-installed-name = crt1.o
+# Similar to crt1.o, but without _IO_stdin_used.
+start-name-2.0 = crt1-2.0.o
 # On systems that do not need a special startfile for statically linked
 # binaries, simply set it to the normal name.
 ifndef static-start-installed-name
@@ -537,6 +539,25 @@ else  # build-static
 endif  # build-shared
 endif  # +link
 
+# Command for linking test programs with crt1.o from glibc 2.0.
++link-2.0-before-inputs = -nostdlib -nostartfiles $(no-pie-ldflag) \
+	      $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \
+	      $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \
+	      $(firstword $(CRT-$(@F)) $(csu-objpfx)$(start-name-2.0)) \
+	      $(+preinit) $(+prector)
++link-2.0-before-libc = -o $@ $(+link-2.0-before-inputs) \
+	      $(filter-out $(addprefix $(csu-objpfx),start.o \
+						     $(start-name-2.0))\
+			   $(+preinit) $(link-extra-libs) \
+			   $(common-objpfx)libc% $(+postinit),$^) \
+	      $(link-extra-libs)
++link-after-libc = $(+postctor) $(+postinit)
+define +link-2.0-tests
+$(CC) $(+link-2.0-before-libc) $(rtld-tests-LDFLAGS) $(link-libc-tests) \
+  $(+link-after-libc)
+$(call after-link,$@)
+endef
+
 # The pretty printer test programs need to be compiled without optimizations
 # so they won't confuse gdb.  We could use either the 'GCC optimize' pragma
 # or the 'optimize' function attribute to achieve this; however, at least on

Rules

@@ -188,6 +188,7 @@ binaries-all = $(binaries-all-notests) $(binaries-all-tests)
 binaries-static-notests = $(others-static)
 binaries-static-tests = $(tests-static) $(xtests-static)
 binaries-static = $(binaries-static-notests) $(binaries-static-tests)
+binaries-shared-2.0-tests = $(tests-2.0)
 ifeq (yesyes,$(have-fpie)$(build-shared))
 binaries-pie-tests = $(tests-pie) $(xtests-pie)
 binaries-pie-notests = $(others-pie)
@@ -215,7 +216,8 @@ binaries-malloc-hugetlb2-tests =
 endif
 
 binaries-pie = $(binaries-pie-tests) $(binaries-pie-notests)
-binaries-shared-tests = $(filter-out $(binaries-pie) $(binaries-static), \
+binaries-shared-tests = $(filter-out $(binaries-pie) $(binaries-static) \
+				     $(binaries-shared-2.0-tests), \
 				     $(binaries-all-tests))
 binaries-shared-notests = $(filter-out $(binaries-pie) $(binaries-static), \
 				       $(binaries-all-notests))
@@ -235,6 +237,15 @@ $(addprefix $(objpfx),$(binaries-shared-tests)): %: %.o \
 	$(+link-tests)
 endif
 
+# Linking test programs with crt1.o from glibc 2.0.
+ifneq "$(strip $(binaries-shared-2.0-tests))" ""
+$(addprefix $(objpfx),$(binaries-shared-2.0-tests)): %: %.o \
+  $(link-extra-libs-tests) \
+  $(sort $(filter $(common-objpfx)lib%,$(link-libc))) \
+  $(addprefix $(csu-objpfx),start.o) $(+preinit) $(+postinit)
+	$(+link-2.0-tests)
+endif
+
 ifneq "$(strip $(binaries-mcheck-tests))" ""
 $(addprefix $(objpfx),$(binaries-mcheck-tests)): %-mcheck: %.o \
   $(link-extra-libs-tests) \

csu/Makefile

@@ -42,6 +42,7 @@ csu-dummies = $(filter-out $(start-installed-name),crt1.o Mcrt1.o)
 extra-objs = \
   $(csu-dummies) \
   $(start-installed-name) \
+  $(start-name-2.0) \
   S$(start-installed-name) \
   g$(start-installed-name) \
   start.o \
@@ -182,6 +183,9 @@ ifndef start-installed-name-rule
 $(objpfx)$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
 				  $(objpfx)init.o $(objpfx)static-reloc.o
 	$(link-relocatable)
+$(objpfx)$(start-name-2.0): $(objpfx)start.o $(objpfx)abi-note.o \
+			    $(objpfx)static-reloc.o
+	$(link-relocatable)
 $(objpfx)r$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
 				  $(objpfx)init.o
 	$(link-relocatable)

libio/Makefile

@@ -266,6 +266,12 @@ aux	:= fileops genops stdfiles stdio strops
 ifeq ($(build-shared),yes)
 generated += tst-bz24228.mtrace tst-bz24228.check
 aux	+= oldfileops oldstdfiles
+tests += \
+  tst-stderr-compat \
+# tests
+tests-2.0 += \
+  tst-stderr-compat \
+# tests-2.0
 endif
 
 shared-only-routines = oldiofopen oldiofdopen oldiofclose oldfileops	\

libio/tst-stderr-compat.c

@@ -0,0 +1,52 @@
+/* Test that fclose works on stderr from glibc 2.0.
+   Copyright (C) 2024 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 <shlib-compat.h>
+
+#if TEST_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
+# define _LIBC
+# define _IO_USE_OLD_IO_FILE
+# include <stdio.h>
+# include <support/check.h>
+
+extern FILE _IO_stderr_;
+compat_symbol_reference (libc, _IO_stderr_, _IO_stderr_, GLIBC_2_0);
+compat_symbol_reference (libc, fclose, fclose, GLIBC_2_0);
+
+__attribute__ ((weak, noclone, noinline))
+void
+do_fclose (FILE *fp)
+{
+  TEST_VERIFY_EXIT (fclose (fp) == 0);
+}
+
+static int
+do_test (void)
+{
+  do_fclose (&_IO_stderr_);
+  return 0;
+}
+#else
+static int
+do_test (void)
+{
+  return 0;
+}
+#endif
+
+#include <support/test-driver.c>

math/Makefile

@@ -566,6 +566,9 @@ tests += \
   test-matherr \
   test-matherr-2 \
   # tests
+tests-2.0 += \
+  test-matherr-2 \
+  # tests-2.0
 endif
 
 # These tests use internal (unexported) GMP functions and are linked

sysdeps/pthread/Makefile

@@ -282,6 +282,10 @@ tests += \
   tst-vfork2x \
   # tests
 
+tests-2.0 += \
+  tst-pthread_kill-exited
+  # tests-2.0
+
 tests-time64 += \
   tst-abstime-time64 \
   tst-cnd-timedwait-time64 \