build: libcody: Link with -lsocket -lnsl if necessary [PR98316]

With the introduction of C++20 modules and libcody, cc1plus and
cc1objplus gained a dependency on the socket functions.  Before those
were merged into libc in Solaris 11.4, one needed to link with -lsocket -lnsl
on Solaris, so that merge broke the Solaris 11.3 build.

While we already have 4 different checks for those libraries in the
tree, I decided to import autoconf-archive's AX_LIB_SOCKET_NSL macro
instead.  At the same time, the patch only links libcody and the
networking libs where needed (cc1plus, cc1objplus).

Bootstrapped without regressions on i386-pc-solaris2.11 (Solaris 11.3
and 11.4), sparc-sun-solaris2.11, and x86_64-pc-linux-gnu.

2020-12-16  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	c++tools:
	PR c++/98316
	* configure.ac: Include ../config/ax_lib_socket_nsl.m4.
	(NETLIBS): Determine using AX_LIB_SOCKET_NSL.
	* configure: Regenerate.
	* Makefile.in (NETLIBS): Define.
	(g++-mapper-server$(exeext)): Add $(NETLIBS).

	gcc/objcp:
	PR c++/98316
	* Make-lang.in (cc1objplus$(exeext)): Add $(CODYLIB), $(NETLIBS).

	gcc/cp:
	PR c++/98316
	* Make-lang.in (cc1plus$(exeext)): Add $(CODYLIB), $(NETLIBS).

	gcc:
	PR c++/98316
	* configure.ac (NETLIBS): Determine using AX_LIB_SOCKET_NSL.
	* aclocal.m4, configure: Regenerate.
	* Makefile.in (NETLIBS): Define.
	(BACKEND): Remove $(CODYLIB).

	config:
	PR c++/98316
	* ax_lib_socket_nsl.m4: Import from autoconf-archive.

1 files changed, 167 insertions, 2 deletions

diff --git a/gcc/configure b/gcc/configure
index ee97603..993ea9d 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -794,6 +794,7 @@ ZSTD_LIB
 ZSTD_INCLUDE
 DL_LIB
 LDEXP_LIB
+NETLIBS
 EXTRA_GCC_LIBS
 GNAT_LIBEXC
 COLLECT2_LIBS
@@ -9866,6 +9867,170 @@ EXTRA_GCC_LIBS="$LIBS"
 LIBS="$save_LIBS"
 
 
+# Solaris needs libsocket and libnsl for socket functions before 11.4.
+# C++ needs those for libcody.
+save_LIBS="$LIBS"
+LIBS=
+
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing gethostbyname" >&5
+$as_echo_n "checking for library containing gethostbyname... " >&6; }
+if ${ac_cv_search_gethostbyname+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char gethostbyname ();
+int
+main ()
+{
+return gethostbyname ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' nsl; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_cxx_try_link "$LINENO"; then :
+  ac_cv_search_gethostbyname=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_gethostbyname+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_gethostbyname+:} false; then :
+
+else
+  ac_cv_search_gethostbyname=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_gethostbyname" >&5
+$as_echo "$ac_cv_search_gethostbyname" >&6; }
+ac_res=$ac_cv_search_gethostbyname
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+fi
+
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing socket" >&5
+$as_echo_n "checking for library containing socket... " >&6; }
+if ${ac_cv_search_socket+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char socket ();
+int
+main ()
+{
+return socket ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' socket; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_cxx_try_link "$LINENO"; then :
+  ac_cv_search_socket=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_socket+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_socket+:} false; then :
+
+else
+  ac_cv_search_socket=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_socket" >&5
+$as_echo "$ac_cv_search_socket" >&6; }
+ac_res=$ac_cv_search_socket
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+else
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for socket in -lsocket" >&5
+$as_echo_n "checking for socket in -lsocket... " >&6; }
+if ${ac_cv_lib_socket_socket+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lsocket -lnsl $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char socket ();
+int
+main ()
+{
+return socket ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_link "$LINENO"; then :
+  ac_cv_lib_socket_socket=yes
+else
+  ac_cv_lib_socket_socket=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_socket_socket" >&5
+$as_echo "$ac_cv_lib_socket_socket" >&6; }
+if test "x$ac_cv_lib_socket_socket" = xyes; then :
+  LIBS="-lsocket -lnsl $LIBS"
+fi
+
+fi
+
+
+NETLIBS="$LIBS"
+LIBS="$save_LIBS"
+
+
 # Some systems put ldexp and frexp in libm instead of libc; assume
 # they're both in the same place.  jcf-dump needs them.
 save_LIBS="$LIBS"
@@ -19237,7 +19402,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19240 "configure"
+#line 19405 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19343,7 +19508,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19346 "configure"
+#line 19511 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H