tests/libexec/ld.elf_so/t_ifunc: Handle MKRELRO=no harder.

Don't even pass -Wl,-z,norelro if MKRELRO=no, because the toolchain's
ld(1) might not support relro _or_ norelro.

Should resolve, e.g.:

/home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407182350Z-tools/bin/armv7--netbsdelf-eabihf-ld: warning: -z norelro ignored
armv7--netbsdelf-eabihf-clang: error: linker command failed with exit code 1 (use -v to see invocation)
--- t_ifunc_norelro ---
*** Failed target: t_ifunc_norelro
*** In directory: /home/source/ab/HEAD-llvm/src/tests/libexec/ld.elf_so
*** Failed commands:
${_MKTARGET_LINK}
...

tests/libexec/ld.elf_so/t_ifunc: Handle MKRELRO=no.

Just build t_ifunc and t_ifunc_now normally. If they wind up being
built with the same options as t_ifunc_norelro and
t_ifunc_norelro_now, so be it; easier to do it this way than to put
more conditionals into set lists.

Should resolve, e.g.:

/home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-tools/bin/armv7--netbsdelf-eabihf-ld: warning: -z relro ignored
armv7--netbsdelf-eabihf-clang: error: linker command failed with exit code 1 (use -v to see invocation)
--- t_ifunc ---
*** Failed target: t_ifunc
*** In directory: /home/source/ab/HEAD-llvm/src/tests/libexec/ld.elf_so
*** Failed commands:
${_MKTARGET_LINK}
=> @# " link " ld.elf_so/t_ifunc
${_CCLINK.${:Ut_ifunc}} ${_LDFLAGS.${:Ut_ifunc}} ${_LDSTATIC.${:Ut_ifunc}} -o ${.TARGET} ${OBJS.${:Ut_ifunc}} ${_PROGLDOPTS} ${_LDADD.${:Ut_ifunc}}
=> /home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-tools/bin/armv7--netbsdelf-eabihf-clang --sysroot=/home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-dest -Wl,--fatal-warnings -Wl,--warn-shared-textrel -pie -o t_ifunc t_ifunc.o -Wl,-rpath-link,/home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-dest/lib -L=/lib -Wl,-z,relro -Wl,-rpath,/usr/tests/libexec/ld.elf_so -lutil -latf-c
${CTFMERGE} ${CTFMFLAGS} -o ${.TARGET} ${OBJS.${:Ut_ifunc}}
=> /home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-tools/bin/nbctfmerge -t -g -L VERSION -g -o t_ifunc t_ifunc.o

t_ifunc: Test with all combinations of {relro, bindnow}.

PR lib/57792

ld.elf_so: Add some known-answer tests for hash functions.

Make sure the testing mechanism detects the traditional overflow bug.

adapt to ${CC_WNO_MAYBE_UNINITIALIZED}

Use ${CC_WNO_MAYBE_UNINITIALIZED} instead of
the older style more complex expressions.

Remove workarounds if they were for a specific
version of gcc < 10.

ld.elf_so: Test dynamic-then-static abuse via ctor.

XXX pullup-10

ld.elf_so: Test another edge case of mismatched TLS models.

One library defines a symbol and _doesn't_ use it, so it has no
indication of whether the symbol is for static TLS or dynamic TLS,
and then two other libraries use it in different ways.

XXX pullup-10

ld.elf_so: Test TLS abuse of static def, dynamic use and vice versa.

XXX pullup-10

ld.elf_so: Test extern dynamic TLS too.

XXX pullup-10

ld.elf_so: Nix inadvertently committed private test program.

ld.elf_so: Fix extern TLS test to match PR toolchain/50277.

Now it's actually testing the problem.

ld.elf_so: New test for extern initial-exec TLS, PR toolchain/50277.

XXX pullup-10

branches: 1.12.4;
Drop explicit -msecure-plt, it's the default for both clang and gcc.

branches: 1.11.2;
Add new RTLD test file for r_debug

New tests:
- self
- dlopen

Both check whether the r_debug structure seems to be well-formed, without
and with a dlopen(3) call.

branches: 1.10.2;
clang ifunc's on powerpc require secure-plt.

branches: 1.9.6;
Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()

tests/libexec/ld.elf_so/t_ifunc: Handle MKRELRO=no.

Just build t_ifunc and t_ifunc_now normally. If they wind up being
built with the same options as t_ifunc_norelro and
t_ifunc_norelro_now, so be it; easier to do it this way than to put
more conditionals into set lists.

Should resolve, e.g.:

/home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-tools/bin/armv7--netbsdelf-eabihf-ld: warning: -z relro ignored
armv7--netbsdelf-eabihf-clang: error: linker command failed with exit code 1 (use -v to see invocation)
--- t_ifunc ---
*** Failed target: t_ifunc
*** In directory: /home/source/ab/HEAD-llvm/src/tests/libexec/ld.elf_so
*** Failed commands:
${_MKTARGET_LINK}
=> @# " link " ld.elf_so/t_ifunc
${_CCLINK.${:Ut_ifunc}} ${_LDFLAGS.${:Ut_ifunc}} ${_LDSTATIC.${:Ut_ifunc}} -o ${.TARGET} ${OBJS.${:Ut_ifunc}} ${_PROGLDOPTS} ${_LDADD.${:Ut_ifunc}}
=> /home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-tools/bin/armv7--netbsdelf-eabihf-clang --sysroot=/home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-dest -Wl,--fatal-warnings -Wl,--warn-shared-textrel -pie -o t_ifunc t_ifunc.o -Wl,-rpath-link,/home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-dest/lib -L=/lib -Wl,-z,relro -Wl,-rpath,/usr/tests/libexec/ld.elf_so -lutil -latf-c
${CTFMERGE} ${CTFMFLAGS} -o ${.TARGET} ${OBJS.${:Ut_ifunc}}
=> /home/builds/ab/HEAD-llvm/evbarm-earmv7hf/202407141900Z-tools/bin/nbctfmerge -t -g -L VERSION -g -o t_ifunc t_ifunc.o

t_ifunc: Test with all combinations of {relro, bindnow}.

PR lib/57792

ld.elf_so: Add some known-answer tests for hash functions.

Make sure the testing mechanism detects the traditional overflow bug.

adapt to ${CC_WNO_MAYBE_UNINITIALIZED}

Use ${CC_WNO_MAYBE_UNINITIALIZED} instead of
the older style more complex expressions.

Remove workarounds if they were for a specific
version of gcc < 10.

ld.elf_so: Test dynamic-then-static abuse via ctor.

XXX pullup-10

ld.elf_so: Test another edge case of mismatched TLS models.

One library defines a symbol and _doesn't_ use it, so it has no
indication of whether the symbol is for static TLS or dynamic TLS,
and then two other libraries use it in different ways.

XXX pullup-10

ld.elf_so: Test TLS abuse of static def, dynamic use and vice versa.

XXX pullup-10

ld.elf_so: Test extern dynamic TLS too.

XXX pullup-10

ld.elf_so: Nix inadvertently committed private test program.

ld.elf_so: Fix extern TLS test to match PR toolchain/50277.

Now it's actually testing the problem.

ld.elf_so: New test for extern initial-exec TLS, PR toolchain/50277.

XXX pullup-10

branches: 1.12.4;
Drop explicit -msecure-plt, it's the default for both clang and gcc.

branches: 1.11.2;
Add new RTLD test file for r_debug

New tests:
- self
- dlopen

Both check whether the r_debug structure seems to be well-formed, without
and with a dlopen(3) call.

branches: 1.10.2;
clang ifunc's on powerpc require secure-plt.

branches: 1.9.6;
Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()

t_ifunc: Test with all combinations of {relro, bindnow}.

PR lib/57792

ld.elf_so: Add some known-answer tests for hash functions.

Make sure the testing mechanism detects the traditional overflow bug.

adapt to ${CC_WNO_MAYBE_UNINITIALIZED}

Use ${CC_WNO_MAYBE_UNINITIALIZED} instead of
the older style more complex expressions.

Remove workarounds if they were for a specific
version of gcc < 10.

ld.elf_so: Test dynamic-then-static abuse via ctor.

XXX pullup-10

ld.elf_so: Test another edge case of mismatched TLS models.

One library defines a symbol and _doesn't_ use it, so it has no
indication of whether the symbol is for static TLS or dynamic TLS,
and then two other libraries use it in different ways.

XXX pullup-10

ld.elf_so: Test TLS abuse of static def, dynamic use and vice versa.

XXX pullup-10

ld.elf_so: Test extern dynamic TLS too.

XXX pullup-10

ld.elf_so: Nix inadvertently committed private test program.

ld.elf_so: Fix extern TLS test to match PR toolchain/50277.

Now it's actually testing the problem.

ld.elf_so: New test for extern initial-exec TLS, PR toolchain/50277.

XXX pullup-10

branches: 1.12.4;
Drop explicit -msecure-plt, it's the default for both clang and gcc.

branches: 1.11.2;
Add new RTLD test file for r_debug

New tests:
- self
- dlopen

Both check whether the r_debug structure seems to be well-formed, without
and with a dlopen(3) call.

branches: 1.10.2;
clang ifunc's on powerpc require secure-plt.

branches: 1.9.6;
Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()

ld.elf_so: Add some known-answer tests for hash functions.

Make sure the testing mechanism detects the traditional overflow bug.

adapt to ${CC_WNO_MAYBE_UNINITIALIZED}

Use ${CC_WNO_MAYBE_UNINITIALIZED} instead of
the older style more complex expressions.

Remove workarounds if they were for a specific
version of gcc < 10.

ld.elf_so: Test dynamic-then-static abuse via ctor.

XXX pullup-10

ld.elf_so: Test another edge case of mismatched TLS models.

One library defines a symbol and _doesn't_ use it, so it has no
indication of whether the symbol is for static TLS or dynamic TLS,
and then two other libraries use it in different ways.

XXX pullup-10

ld.elf_so: Test TLS abuse of static def, dynamic use and vice versa.

XXX pullup-10

ld.elf_so: Test extern dynamic TLS too.

XXX pullup-10

ld.elf_so: Nix inadvertently committed private test program.

ld.elf_so: Fix extern TLS test to match PR toolchain/50277.

Now it's actually testing the problem.

ld.elf_so: New test for extern initial-exec TLS, PR toolchain/50277.

XXX pullup-10

Drop explicit -msecure-plt, it's the default for both clang and gcc.

branches: 1.11.2;
Add new RTLD test file for r_debug

New tests:
- self
- dlopen

Both check whether the r_debug structure seems to be well-formed, without
and with a dlopen(3) call.

clang ifunc's on powerpc require secure-plt.

branches: 1.9.6;
Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()

adapt to ${CC_WNO_MAYBE_UNINITIALIZED}

Use ${CC_WNO_MAYBE_UNINITIALIZED} instead of
the older style more complex expressions.

Remove workarounds if they were for a specific
version of gcc < 10.

ld.elf_so: Test dynamic-then-static abuse via ctor.

XXX pullup-10

ld.elf_so: Test another edge case of mismatched TLS models.

One library defines a symbol and _doesn't_ use it, so it has no
indication of whether the symbol is for static TLS or dynamic TLS,
and then two other libraries use it in different ways.

XXX pullup-10

ld.elf_so: Test TLS abuse of static def, dynamic use and vice versa.

XXX pullup-10

ld.elf_so: Test extern dynamic TLS too.

XXX pullup-10

ld.elf_so: Nix inadvertently committed private test program.

ld.elf_so: Fix extern TLS test to match PR toolchain/50277.

Now it's actually testing the problem.

ld.elf_so: New test for extern initial-exec TLS, PR toolchain/50277.

XXX pullup-10

Drop explicit -msecure-plt, it's the default for both clang and gcc.

branches: 1.11.2;
Add new RTLD test file for r_debug

New tests:
- self
- dlopen

Both check whether the r_debug structure seems to be well-formed, without
and with a dlopen(3) call.

clang ifunc's on powerpc require secure-plt.

branches: 1.9.6;
Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()

Drop explicit -msecure-plt, it's the default for both clang and gcc.

Add new RTLD test file for r_debug

New tests:
- self
- dlopen

Both check whether the r_debug structure seems to be well-formed, without
and with a dlopen(3) call.

clang ifunc's on powerpc require secure-plt.

branches: 1.9.6;
Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()

Add new RTLD test file for r_debug

New tests:
- self
- dlopen

Both check whether the r_debug structure seems to be well-formed, without
and with a dlopen(3) call.

clang ifunc's on powerpc require secure-plt.

branches: 1.9.6;
Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()

clang ifunc's on powerpc require secure-plt.

Implement __cxa_thread_atexit and __cxa_thread_atexit_impl. This
functions are used for destructors of thread_local objects.

If a pending destructor exists, prevent unloading of shared objects.
Introduce __dl_cxa_refcount interface for this purpose. When the last
reference is gone and the object has been dlclose'd before, the
unloading is finalized.

Ideally, __cxa_thread_atexit_impl wouldn't exist, but libstdc++ insists
on providing __cxa_thread_atexit as direct wrapper without further
patching.

branches: 1.8.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

avoid building stuff that depends upon pic objects if MKPIC == no.

only build the ld.elf_so tests if MKPIC != no.

PR/45015: ld.elf_so: support ELF symbol versioning
Applied latest patch.

Add initial regression test for ld.elf_so locking.

Add support for DF_1_BIND_NOW, DF_1_NODELETE and DF_1_NOOPEN marked
objects, and the RTLD_NODELETE and RTLD_NOLOAD flags to dlopen(3).

Mark libpthread as DF_1_NOOPEN and use it to test the functionality.

Somewhat taken from FreeBSD.

Fixes PR 42029.

OK from christos and joerg.

Convert a couple of old regress tests to ATF.

Remove the regress/usr.bin/rtld/dlopen/dlopen.c test as well as it's
covered by existing ATF test(s).

add regression tests for dlinfo()