From 2dad10f467165ad87dace65ae9aa1cf19fae0867 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 18 May 2008 20:13:12 +0000
Subject: [PATCH] Make another try at using -Wl,--as-needed to suppress linking
 of unnecessary shared libraries.  We've tried this before and had problems
 with libreadline not linking properly on some platforms, but that seems to be
 a libreadline bug that may have been fixed by now.  In any case, it's early
 enough in the 8.4 devel cycle that we can afford to have some transient
 breakage while we work out any portability problems.

On Darwin, we try -Wl,-dead_strip_dylibs, which seems to be the equivalent
incantation there.
---
 config/c-compiler.m4 |  18 ++++++-
 configure            | 110 +++++++++++++++++++++++++++++++++++++++++++
 configure.in         |  12 ++++-
 3 files changed, 138 insertions(+), 2 deletions(-)

diff --git a/config/c-compiler.m4 b/config/c-compiler.m4
index cc25cf94ba..2e3fba877a 100644
--- a/config/c-compiler.m4
+++ b/config/c-compiler.m4
@@ -1,5 +1,5 @@
 # Macros to detect C compiler features
-# $PostgreSQL: pgsql/config/c-compiler.m4,v 1.16 2008/04/18 18:43:08 alvherre Exp $
+# $PostgreSQL: pgsql/config/c-compiler.m4,v 1.17 2008/05/18 20:13:12 tgl Exp $
 
 
 # PGAC_C_SIGNED
@@ -110,3 +110,19 @@ _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
                    [CFLAGS="$pgac_save_CFLAGS"
                     AC_MSG_RESULT(no)])
 ])# PGAC_PROG_CC_CFLAGS_OPT
+
+
+
+# PGAC_PROG_CC_LDFLAGS_OPT
+# ------------------------
+# Given a string, check if the compiler supports the string as a
+# command-line option. If it does, add the string to LDFLAGS.
+AC_DEFUN([PGAC_PROG_CC_LDFLAGS_OPT],
+[AC_MSG_CHECKING([if $CC supports $1])
+pgac_save_LDFLAGS=$LDFLAGS
+LDFLAGS="$pgac_save_LDFLAGS $1"
+AC_LINK_IFELSE([AC_LANG_PROGRAM()],
+               AC_MSG_RESULT(yes),
+               [LDFLAGS="$pgac_save_LDFLAGS"
+                AC_MSG_RESULT(no)])
+])# PGAC_PROG_CC_LDFLAGS_OPT
diff --git a/configure b/configure
index f71fcd642d..20d1f5b4a9 100755
--- a/configure
+++ b/configure
@@ -4318,6 +4318,116 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
+# If compiler will take -Wl,--as-needed then add that to LDFLAGS.
+# This is much easier than trying to filter LIBS to the minimum for each
+# executable.  (Note that shared libraries won't use this switch, though.)
+# On Darwin it's spelled -Wl,-dead_strip_dylibs, but don't try that elsewhere
+if test "$PORTNAME" != "darwin"; then
+  { echo "$as_me:$LINENO: checking if $CC supports -Wl,--as-needed" >&5
+echo $ECHO_N "checking if $CC supports -Wl,--as-needed... $ECHO_C" >&6; }
+pgac_save_LDFLAGS=$LDFLAGS
+LDFLAGS="$pgac_save_LDFLAGS -Wl,--as-needed"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+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=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext &&
+       $as_test_x conftest$ac_exeext; then
+  { echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6; }
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	LDFLAGS="$pgac_save_LDFLAGS"
+                { echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+
+else
+  { echo "$as_me:$LINENO: checking if $CC supports -Wl,-dead_strip_dylibs" >&5
+echo $ECHO_N "checking if $CC supports -Wl,-dead_strip_dylibs... $ECHO_C" >&6; }
+pgac_save_LDFLAGS=$LDFLAGS
+LDFLAGS="$pgac_save_LDFLAGS -Wl,-dead_strip_dylibs"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+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=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext &&
+       $as_test_x conftest$ac_exeext; then
+  { echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6; }
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	LDFLAGS="$pgac_save_LDFLAGS"
+                { echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+
+fi
+
 # Create compiler version string
 if test x"$GCC" = x"yes" ; then
   cc_string="GCC `${CC} --version | sed q`"
diff --git a/configure.in b/configure.in
index b8f8396030..a888e35274 100644
--- a/configure.in
+++ b/configure.in
@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.560 2008/05/03 00:24:05 adunstan Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.561 2008/05/18 20:13:12 tgl Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -450,6 +450,16 @@ fi
 AC_PROG_CPP
 AC_SUBST(GCC)
 
+# If compiler will take -Wl,--as-needed then add that to LDFLAGS.
+# This is much easier than trying to filter LIBS to the minimum for each
+# executable.  (Note that shared libraries won't use this switch, though.)
+# On Darwin it's spelled -Wl,-dead_strip_dylibs, but don't try that elsewhere
+if test "$PORTNAME" != "darwin"; then
+  PGAC_PROG_CC_LDFLAGS_OPT([-Wl,--as-needed])
+else
+  PGAC_PROG_CC_LDFLAGS_OPT([-Wl,-dead_strip_dylibs])
+fi
+
 # Create compiler version string
 if test x"$GCC" = x"yes" ; then
   cc_string="GCC `${CC} --version | sed q`"
-- 
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