ASan, UBSan and MSan provided by clang aren't compatible with --no-undefined 
and -z,defs:
https://clang.llvm.org/docs/AddressSanitizer.html#usage
https://github.com/google/sanitizers/issues/380
so to build elfutils with clang with the sanitizers it should be possible
to turn them off.

Without this patch something like

sed -i 's/^\(ZDEFS_LDFLAGS=\).*/\1/' configure.ac
find -name Makefile.am | xargs sed -i 's/,--no-undefined//'

should be used to make elfutils compile.

Issues like https://bugs.llvm.org/show_bug.cgi?id=30333 have been
open since at least 2016 so it seems it's safe to say that it isn't
going to be fixed anytime soon. It's so ingrained that some build
systems complain when `-fsanitize=...` is passed to clang without
turning off no-undefined.

The patch was tested in https://github.com/evverx/elfutils/pull/24 by
compiling elfutils with both gcc and clang with and without ASan/UBsan
and running `make check && make distcheck`. --no-undefined and -z,defs
are still passed by default as expected.

Signed-off-by: Evgeny Vereshchagin <evv...@ya.ru>
---
 ChangeLog              |  5 +++++
 configure.ac           | 31 ++++++++++++++++++++++---------
 debuginfod/Makefile.am |  2 +-
 libasm/Makefile.am     |  2 +-
 libdw/Makefile.am      |  2 +-
 libelf/Makefile.am     |  2 +-
 6 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d61b21c7..33d20be5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2021-12-03  Evgeny Vereshchagin  <evv...@ya.ru>
+
+       * configure.ac [--disable-no-undefined]: Allow turning off
+       --no-undefined and -z,defs to build elfutils with clang sanitizers.
+
 2021-11-10  Mark Wielaard  <m...@klomp.org>
 
        * configure.ac (AC_INIT): Set version to 0.186.
diff --git a/configure.ac b/configure.ac
index ff9581d2..14cd2e6f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -153,16 +153,29 @@ AC_SUBST([fpie_CFLAGS])
 
 dso_LDFLAGS="-shared"
 
-ZDEFS_LDFLAGS="-Wl,-z,defs"
-AC_CACHE_CHECK([whether gcc supports $ZDEFS_LDFLAGS], ac_cv_zdefs, [dnl
-save_LDFLAGS="$LDFLAGS"
-LDFLAGS="$ZDEFS_LDFLAGS $save_LDFLAGS"
-AC_LINK_IFELSE([AC_LANG_PROGRAM()], ac_cv_zdefs=yes, ac_cv_zdefs=no)
-LDFLAGS="$save_LDFLAGS"
-])
-if test "$ac_cv_zdefs" = "yes"; then
-       dso_LDFLAGS="$dso_LDFLAGS $ZDEFS_LDFLAGS"
+# ASan, UBSan and MSan provided by clang aren't compatible with --no-undefined 
and -z,defs:
+# https://clang.llvm.org/docs/AddressSanitizer.html#usage
+# https://github.com/google/sanitizers/issues/380
+# so to build elfutils with clang with the sanitizers it should be possible
+# to turn them off.
+AC_ARG_ENABLE([no-undefined],
+AS_HELP_STRING([--disable-no-undefined],[disable --no-undefined and -z,defs]),
+[use_no_undefined=$enableval], [use_no_undefined=yes])
+if test "$use_no_undefined" = yes; then
+       ZDEFS_LDFLAGS="-Wl,-z,defs"
+       AC_CACHE_CHECK([whether gcc supports $ZDEFS_LDFLAGS], ac_cv_zdefs, [dnl
+       save_LDFLAGS="$LDFLAGS"
+       LDFLAGS="$ZDEFS_LDFLAGS $save_LDFLAGS"
+       AC_LINK_IFELSE([AC_LANG_PROGRAM()], ac_cv_zdefs=yes, ac_cv_zdefs=no)
+       LDFLAGS="$save_LDFLAGS"
+       ])
+       if test "$ac_cv_zdefs" = "yes"; then
+               dso_LDFLAGS="$dso_LDFLAGS $ZDEFS_LDFLAGS"
+       fi
+
+       NO_UNDEFINED=",--no-undefined"
 fi
+AC_SUBST([NO_UNDEFINED])
 
 # We really want build-ids. Warn and force generating them if gcc was
 # configure without --enable-linker-build-id
diff --git a/debuginfod/Makefile.am b/debuginfod/Makefile.am
index 3adb2755..58bf71d3 100644
--- a/debuginfod/Makefile.am
+++ b/debuginfod/Makefile.am
@@ -102,7 +102,7 @@ endif
 $(LIBDEBUGINFOD_SONAME): $(srcdir)/libdebuginfod.map $(libdebuginfod_so_LIBS)
        $(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
                -Wl,--soname,$(LIBDEBUGINFOD_SONAME) \
-               -Wl,--version-script,$<,--no-undefined \
+               -Wl,--version-script,$<$(NO_UNDEFINED) \
                -Wl,--whole-archive $(libdebuginfod_so_LIBS) 
-Wl,--no-whole-archive \
                $(libdebuginfod_so_LDLIBS)
        @$(textrel_check)
diff --git a/libasm/Makefile.am b/libasm/Makefile.am
index c2b54811..683c9847 100644
--- a/libasm/Makefile.am
+++ b/libasm/Makefile.am
@@ -64,7 +64,7 @@ libasm_so_LIBS = libasm_pic.a
 libasm.so: $(srcdir)/libasm.map $(libasm_so_LIBS) $(libasm_so_DEPS)
        $(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
                -Wl,--soname,$@.$(VERSION) \
-               -Wl,--version-script,$<,--no-undefined \
+               -Wl,--version-script,$<$(NO_UNDEFINED) \
                -Wl,--whole-archive $(libasm_so_LIBS) -Wl,--no-whole-archive \
                $(libasm_so_LDLIBS)
        @$(textrel_check)
diff --git a/libdw/Makefile.am b/libdw/Makefile.am
index 4fda33bd..534e5cc7 100644
--- a/libdw/Makefile.am
+++ b/libdw/Makefile.am
@@ -114,7 +114,7 @@ libdw_so_LDLIBS = $(libdw_so_DEPS) -ldl -lz $(argp_LDADD) 
$(fts_LIBS) $(obstack_
 libdw.so: $(srcdir)/libdw.map $(libdw_so_LIBS) $(libdw_so_DEPS)
        $(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
                -Wl,--soname,$@.$(VERSION),--enable-new-dtags \
-               -Wl,--version-script,$<,--no-undefined \
+               -Wl,--version-script,$<$(NO_UNDEFINED) \
                -Wl,--whole-archive $(libdw_so_LIBS) -Wl,--no-whole-archive \
                $(libdw_so_LDLIBS)
        @$(textrel_check)
diff --git a/libelf/Makefile.am b/libelf/Makefile.am
index 560ed45f..034b7a0d 100644
--- a/libelf/Makefile.am
+++ b/libelf/Makefile.am
@@ -115,7 +115,7 @@ libelf_so_LIBS = libelf_pic.a
 libelf.so: $(srcdir)/libelf.map $(libelf_so_LIBS) $(libelf_so_DEPS)
        $(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
                -Wl,--soname,$@.$(VERSION) \
-               -Wl,--version-script,$<,--no-undefined \
+               -Wl,--version-script,$<$(NO_UNDEFINED) \
                -Wl,--whole-archive $(libelf_so_LIBS) -Wl,--no-whole-archive \
                $(libelf_so_LDLIBS)
        @$(textrel_check)
-- 
2.31.1

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