[PATCH] Check if linker supports -Wl,--undefined-version

[Adhemerval Zanella]

Although binutils has supported --no-undefined-version for a long timei
(319416359200 back in 2002), --undefined-version was only added more
recently (27fb6a1a7fcd on 2.40).
---
 Makerules    |  2 +-
 configure    | 36 ++++++++++++++++++++++++++++++++++++
 configure.ac |  6 ++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/Makerules b/Makerules
index caa1e43faa..89ef44d7c5 100644
--- a/Makerules
+++ b/Makerules
@@ -510,7 +510,7 @@ map-file = $(firstword $($(@F:.so=-map)) \
 				   $(filter $(@F:.so=.map),$(version-maps))))
 # The map version is created with multiple symbols that might not be
 # exported depending of the ABI.
-load-map-file = $(map-file:%=-Wl,--version-script=%) -Wl,--undefined-version
+load-map-file = $(map-file:%=-Wl,--version-script=%) $(have-undefined-version)
 endif
 
 # Compiler arguments to use to link a shared object with libc and
diff --git a/configure b/configure
index 1999d12f44..d5bd639586 100755
--- a/configure
+++ b/configure
@@ -9246,6 +9246,42 @@ printf "%s\n" "$libc_linker_feature" >&6; }
 config_vars="$config_vars
 have-ld-gcs = $libc_cv_ld_gcs"
 
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports --undefined-version" >&5
+printf %s "checking for linker that supports --undefined-version... " >&6; }
+libc_linker_feature=no
+cat > conftest.c <<EOF
+int _start (void) { return 42; }
+EOF
+if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
+		  -Wl,--undefined-version -nostdlib -nostartfiles
+		  -fPIC -shared -o conftest.so conftest.c
+		  1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then
+  if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,--undefined-version -nostdlib \
+      -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
+      | grep "warning: --undefined-version ignored" > /dev/null 2>&1; then
+    true
+  else
+    libc_linker_feature=yes
+  fi
+fi
+rm -f conftest*
+if test $libc_linker_feature = yes; then
+  libc_cv_ld_undefined_version=-Wl,--undefined-version
+else
+  libc_cv_ld_undefined_version=
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5
+printf "%s\n" "$libc_linker_feature" >&6; }
+config_vars="$config_vars
+have-undefined-version = $libc_cv_ld_undefined_version"
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can build programs as PIE" >&5
 printf %s "checking if we can build programs as PIE... " >&6; }
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
diff --git a/configure.ac b/configure.ac
index 46a354dfbc..aaf686494a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2066,6 +2066,12 @@ LIBC_LINKER_FEATURE([-z gcs=always], [-Wl,-z,gcs=always],
 		    [libc_cv_ld_gcs=yes], [libc_cv_ld_gcs=no])
 LIBC_CONFIG_VAR([have-ld-gcs], [$libc_cv_ld_gcs])
 
+
+LIBC_LINKER_FEATURE([--undefined-version], [-Wl,--undefined-version],
+		    [libc_cv_ld_undefined_version=-Wl,--undefined-version],
+		    [libc_cv_ld_undefined_version=])
+LIBC_CONFIG_VAR([have-undefined-version], [$libc_cv_ld_undefined_version])
+
 AC_MSG_CHECKING(if we can build programs as PIE)
 AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED
 # error PIE is not supported
-- 
2.43.0