From 505ea90904436e6477f24c8d9775762ca4b29e7b Mon Sep 17 00:00:00 2001
From: Jonathan Yong <10walls@gmail.com>
Date: Wed, 11 Nov 2020 15:21:26 +0000
Subject: [PATCH] libstdc++: Exclude cygwin and mingw from linker relro support

PE format does not have ELF style relro linker support, exclude
from checking. If the host linker supports ELF format, configure
may get confused.

libstdc++-v3/ChangeLog:

	* acinclude.m4 (GLIBCXX_CHECK_LINKER_FEATURES): Exclude
	cygwin and mingw from relro linker test.
	* configure: Regenerate.
---
 libstdc++-v3/acinclude.m4 |  23 ++--
 libstdc++-v3/configure    | 230 ++++++++++++++++++++++++++------------
 2 files changed, 176 insertions(+), 77 deletions(-)

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index b9452dd74cd..650d63ab3d7 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -273,13 +273,22 @@ AC_DEFUN([GLIBCXX_CHECK_LINKER_FEATURES], [
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    AC_MSG_CHECKING([for ld that supports -Wl,-z,relro])
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    AC_MSG_RESULT($ac_ld_relro)
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      AC_MSG_CHECKING([for ld that supports -Wl,-z,relro])
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      AC_MSG_RESULT($ac_ld_relro)
+    esac
   fi
 
   # Set linker optimization flags.
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index efdec6e68b9..1997c1fce4a 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -22936,15 +22936,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -30131,15 +30140,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -36054,15 +36072,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -47976,15 +48003,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -48252,15 +48288,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -48719,15 +48764,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -55098,15 +55152,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -61029,15 +61092,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -61230,15 +61302,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
@@ -61450,15 +61531,24 @@ $as_echo "$ac_gcsections" >&6; }
   # Note this is only for shared objects.
   ac_ld_relro=no
   if test x"$with_gnu_ld" = x"yes"; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
+    # cygwin and mingw uses PE, which has no ELF relro support,
+    # multi target ld may confuse configure machinery
+    case "$host" in
+    *-*-cygwin*)
+     ;;
+    *-*-mingw*)
+     ;;
+    *)
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ld that supports -Wl,-z,relro" >&5
 $as_echo_n "checking for ld that supports -Wl,-z,relro... " >&6; }
-    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
-    if test -n "$cxx_z_relo"; then
-      OPT_LDFLAGS="-Wl,-z,relro"
-      ac_ld_relro=yes
-    fi
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
+      cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
+      if test -n "$cxx_z_relo"; then
+        OPT_LDFLAGS="-Wl,-z,relro"
+        ac_ld_relro=yes
+      fi
+      { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ld_relro" >&5
 $as_echo "$ac_ld_relro" >&6; }
+    esac
   fi
 
   # Set linker optimization flags.
-- 
2.30.2