Use --as-needed when linking libpython3.so. Closes #11347.

Patch by Arfrever Frehtes Taifersar Arahesis.

Makefile.pre.in

@@ -76,6 +76,7 @@ PY_CFLAGS=	$(BASECFLAGS) $(OPT) $(CONFIGURE_CFLAGS) $(CFLAGS) $(EXTRA_CFLAGS)
 # environment variables
 PY_CPPFLAGS=	-I. -IInclude -I$(srcdir)/Include $(CONFIGURE_CPPFLAGS) $(CPPFLAGS)
 PY_LDFLAGS=	$(CONFIGURE_LDFLAGS) $(LDFLAGS)
+NO_AS_NEEDED=	@NO_AS_NEEDED@
 LDLAST=		@LDLAST@
 SGI_ABI=	@SGI_ABI@
 CCSHARED=	@CCSHARED@
@@ -459,7 +460,7 @@ libpython$(LDVERSION).so: $(LIBRARY_OBJS)
 	fi
 
 libpython3.so:	libpython$(LDVERSION).so
-	$(BLDSHARED) -o $@ -Wl,-hl$@ $^
+	$(BLDSHARED) $(NO_AS_NEEDED) -o $@ -Wl,-h$@ $^
 
 libpython$(LDVERSION).dylib: $(LIBRARY_OBJS)
 	 $(CC) -dynamiclib -Wl,-single_module $(PY_LDFLAGS) -undefined dynamic_lookup -Wl,-install_name,$(prefix)/lib/libpython$(LDVERSION).dylib -Wl,-compatibility_version,$(VERSION) -Wl,-current_version,$(VERSION) -o $@ $(LIBRARY_OBJS) $(SHLIBS) $(LIBC) $(LIBM) $(LDLAST); \

Misc/NEWS

@@ -313,6 +313,8 @@ Library
 Build
 -----
 
+- Issue #11347: Use --as-needed when linking libpython3.so.
+
 - Issue #11411: Fix 'make DESTDIR=' with a relative destination.
 
 - Issue #11268: Prevent Mac OS X Installer failure if Documentation

configure

@@ -668,6 +668,7 @@ BUILDEXEEXT
 EGREP
 GREP
 CPP
+NO_AS_NEEDED
 MAINCC
 CXX
 OBJEXT
@@ -1572,6 +1573,52 @@ fi
 
 } # ac_fn_c_try_compile
 
+# ac_fn_c_try_link LINENO
+# -----------------------
+# Try to link conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_link ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  rm -f conftest.$ac_objext conftest$ac_exeext
+  if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+$as_echo "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext && {
+	 test "$cross_compiling" = yes ||
+	 $as_test_x conftest$ac_exeext
+       }; then :
+  ac_retval=0
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_retval=1
+fi
+  # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information
+  # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would
+  # interfere with the next link command; also delete a directory that is
+  # left behind by Apple's compiler.  We do this before executing the actions.
+  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_link
+
 # ac_fn_c_try_cpp LINENO
 # ----------------------
 # Try to preprocess conftest.$ac_ext, and return whether this succeeded.
@@ -1773,52 +1820,6 @@ $as_echo "$ac_res" >&6; }
 
 } # ac_fn_c_check_header_compile
 
-# ac_fn_c_try_link LINENO
-# -----------------------
-# Try to link conftest.$ac_ext, and return whether this succeeded.
-ac_fn_c_try_link ()
-{
-  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  rm -f conftest.$ac_objext conftest$ac_exeext
-  if { { ac_try="$ac_link"
-case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
-$as_echo "$ac_try_echo"; } >&5
-  (eval "$ac_link") 2>conftest.err
-  ac_status=$?
-  if test -s conftest.err; then
-    grep -v '^ *+' conftest.err >conftest.er1
-    cat conftest.er1 >&5
-    mv -f conftest.er1 conftest.err
-  fi
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; } && {
-	 test -z "$ac_c_werror_flag" ||
-	 test ! -s conftest.err
-       } && test -s conftest$ac_exeext && {
-	 test "$cross_compiling" = yes ||
-	 $as_test_x conftest$ac_exeext
-       }; then :
-  ac_retval=0
-else
-  $as_echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-	ac_retval=1
-fi
-  # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information
-  # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would
-  # interfere with the next link command; also delete a directory that is
-  # left behind by Apple's compiler.  We do this before executing the actions.
-  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
-  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
-  as_fn_set_status $ac_retval
-
-} # ac_fn_c_try_link
-
 # ac_fn_c_check_type LINENO TYPE VAR INCLUDES
 # -------------------------------------------
 # Tests whether TYPE exists after having included INCLUDES, setting cache
@@ -4168,8 +4169,38 @@ $as_echo "$as_me: WARNING:
 fi
 
 
-# checks for UNIX variants that set C preprocessor variables
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for -Wl,--no-as-needed" >&5
+$as_echo_n "checking for -Wl,--no-as-needed... " >&6; }
+save_LDFLAGS="$LDFLAGS"
+LDFLAGS="$LDFLAGS -Wl,--no-as-needed"
 
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  NO_AS_NEEDED="-Wl,--no-as-needed"
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  NO_AS_NEEDED=""
+   { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LDFLAGS="$save_LDFLAGS"
+
+
+
+# checks for UNIX variants that set C preprocessor variables
 ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'

configure.in

@@ -525,6 +525,18 @@ then
 fi
 
 
+AC_MSG_CHECKING([for -Wl,--no-as-needed])
+save_LDFLAGS="$LDFLAGS"
+LDFLAGS="$LDFLAGS -Wl,--no-as-needed"
+AC_LINK_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
+  [NO_AS_NEEDED="-Wl,--no-as-needed"
+   AC_MSG_RESULT([yes])],
+  [NO_AS_NEEDED=""
+   AC_MSG_RESULT([no])])
+LDFLAGS="$save_LDFLAGS"
+AC_SUBST(NO_AS_NEEDED)
+
+
 # checks for UNIX variants that set C preprocessor variables
 AC_USE_SYSTEM_EXTENSIONS