[gcc r12-5321] configure, Darwin: Set appropriate defaults for host-shared.

[Iain D Sandoe <iains@gcc.gnu.org>]

https://gcc.gnu.org/g:a1d2b16202601e597fac1c0e6af6ee8cd09b52c0

commit r12-5321-ga1d2b16202601e597fac1c0e6af6ee8cd09b52c0
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Fri Nov 12 17:05:13 2021 +0000

    configure, Darwin: Set appropriate defaults for host-shared.
    
    Darwin x86_64 and aarch64 platforms are PIC (shared) by default,
    and user-space code must be built in this mode.  The patch
    ensures that this is set correctly and applies a default when
    --enable-host-shared is not set.
    
    Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
    
    ChangeLog:
    
            * configure: Regenerate.
            * configure.ac: Ensure that PIC (shared) defaults are set
            correctly for Darwin.

Diff:
---
 configure    | 16 +++++++++++++++-
 configure.ac | 15 ++++++++++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index 58979d6e3b1..3062495da31 100755
--- a/configure
+++ b/configure
@@ -8447,8 +8447,20 @@ fi
 # Check whether --enable-host-shared was given.
 if test "${enable_host_shared+set}" = set; then :
   enableval=$enable_host_shared; host_shared=$enableval
+ case $target in
+   x86_64-*-darwin* | aarch64-*-darwin*)
+     if test x$host_shared != xyes ; then
+       # PIC is the default, and actually cannot be switched off.
+       echo configure.ac: warning: PIC code is required for the configured target, host-shared setting ignored. 1>&2
+       host_shared=yes
+     fi ;;
+  *) ;;
+ esac
 else
-  host_shared=no
+  case $target in
+  x86_64-*-darwin* | aarch64-*-darwin*) host_shared=yes ;;
+  *) host_shared=no ;;
+ esac
 fi
 
 
@@ -10083,6 +10095,8 @@ done
 
 
 
+
+
 # Generate default definitions for YACC, M4, LEX and other programs that run
 # on the build machine.  These are used if the Makefile can't locate these
 # programs in objdir.
diff --git a/configure.ac b/configure.ac
index 550e6993b59..bed60bcaf72 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1859,7 +1859,20 @@ AC_SUBST(extra_linker_plugin_flags)
 AC_ARG_ENABLE(host-shared,
 [AS_HELP_STRING([--enable-host-shared],
 		[build host code as shared libraries])],
-[host_shared=$enableval], [host_shared=no])
+[host_shared=$enableval
+ case $target in
+   x86_64-*-darwin* | aarch64-*-darwin*)
+     if test x$host_shared != xyes ; then
+       # PIC is the default, and actually cannot be switched off.
+       echo configure.ac: warning: PIC code is required for the configured target, host-shared setting ignored. 1>&2
+       host_shared=yes
+     fi ;;
+  *) ;;
+ esac],
+[case $target in
+  x86_64-*-darwin* | aarch64-*-darwin*) host_shared=yes ;;
+  *) host_shared=no ;;
+ esac])
 AC_SUBST(host_shared)
 
 # By default, C and C++ are the only stage 1 languages.