Part 1: drop legacy library build for macOS >= 14 [PR116809].

This is a mixture of two upstream patches.  See

     https://github.com/gcc-mirror/gcc/blob/master/libgcc/config.host

libgcc, Darwin: Drop the legacy library build for macOS >= 15 [PR116809].

We have been building a legacy libgcc_s.1 DSO to support code that
was built with older compilers.

From macOS 15, the unwinder no longer exports some of the symbols used
in that library which (a) cuases bootstrap fail and (b) means that the
legacy library is no longer useful.

No open branch of GCC emits references to this library - and any already
-built code that depends on the symbols would need rework anyway.

	PR target/116809

libgcc, Darwin: Don't build legacy libgcc_s.1 on macOS 14 [PR116809]

d9cafa0 stopped building libgcc_s.1 on macOS >= 15, in part because
that is required to bootstrap the compiler using the macOS 15 SDK. The
macOS 15 SDK ships in Xcode 16, which also runs on macOS 14. libgcc_s.1
can no longer be built on macOS 14 using Xcode 16 by the same logic that
the previous change disabled it for macOS 15.

	PR target/116809

Parts 2-3: This is needed for arm64 to get Out-of-line LSE atomics linked into libgcc.
libsupc++ fails to link without this, and for arm to build.

--- libgcc/config.host.orig	2024-06-20 08:08:09.000000000 +0000
+++ libgcc/config.host
@@ -243,19 +243,25 @@ case ${host} in
   tmake_file="$tmake_file t-slibgcc-darwin"
   # newer toolsets produce warnings when building for unsupported versions.
   case ${host} in
-    *-*-darwin1[89]* | *-*-darwin2* )
-      tmake_file="t-darwin-min-8 $tmake_file"
+    x86_64-*-darwin2[0-2]*)
+      tmake_file="t-darwin-min-11 t-darwin-libgccs1 $tmake_file"
+      ;;
+    *-*-darwin2*)
+      tmake_file="t-darwin-min-11 $tmake_file"
+      ;;
+    *-*-darwin1[89]*)
+      tmake_file="t-darwin-min-8 t-darwin-libgccs1 $tmake_file"
       ;;
     *-*-darwin9* | *-*-darwin1[0-7]*)
-      tmake_file="t-darwin-min-5 $tmake_file"
+      tmake_file="t-darwin-min-5 t-darwin-libgccs1 $tmake_file"
       ;;
     *-*-darwin[4-8]*)
-      tmake_file="t-darwin-min-1 $tmake_file"
+      tmake_file="t-darwin-min-1 t-darwin-libgccs1 $tmake_file"
       ;;
     *)
       # Fall back to configuring for the oldest system known to work with
       # all archs and the current sources.
-      tmake_file="t-darwin-min-5 $tmake_file"
+      tmake_file="t-darwin-min-5 t-darwin-libgccs1 $tmake_file"
       echo "Warning: libgcc configured to support macOS 10.5" 1>&2
       ;;
   esac
@@ -412,6 +418,7 @@ aarch64*-*-freebsd*)
 aarch64*-*-netbsd*)
 	extra_parts="$extra_parts crtfastmath.o"
 	tmake_file="${tmake_file} ${cpu_type}/t-aarch64"
+	tmake_file="${tmake_file} ${cpu_type}/t-lse"
 	tmake_file="${tmake_file} ${cpu_type}/t-softfp t-softfp t-crtfm"
 	md_unwind_header=aarch64/aarch64-unwind.h
 	;;
@@ -499,7 +506,8 @@ arm*-*-netbsdelf*)
 	case ${host} in
 	  arm*-*-netbsdelf-*eabi*)
 	    tmake_file="${tmake_file} arm/t-netbsd-eabi"
-	    unwind_header=config/arm/unwind-arm.h
+	    # GCC 7 vs NetBSD/eabi -> avoid arm unwinder
+	    #unwind_header=config/arm/unwind-arm.h
 	    ;;
 	  *)
 	    tmake_file="${tmake_file} arm/t-netbsd t-slibgcc-gld-nover"


libgcc, Darwin: Drop the legacy library build for macOS >= 15 [PR116809].

We have been building a legacy libgcc_s.1 DSO to support code that
was built with older compilers.

From macOS 15,  the unwinder no longer exports some of the symbols used
in that library which (a) cuases bootstrap fail and (b) means that the
legacy library is no longer useful.

No open branch of GCC emits references to this library - and any already
-built code that depends on the symbols would need rework anyway.

	PR target/116809

See https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/i386/t-darwin.

--- libgcc/config/i386/t-darwin.orig	2024-05-21 07:47:41.000000000 +0000
+++ libgcc/config/i386/t-darwin
@@ -4,6 +4,3 @@ LIB2FUNCS_EXCLUDE = _fixtfdi _fixunstfdi
 
 # Extra symbols for this port.
 SHLIB_MAPFILES += $(srcdir)/config/i386/libgcc-darwin.ver
-
-# Build a legacy libgcc_s.1
-BUILD_LIBGCCS1 = YES


libgcc, Darwin: Drop the legacy library build for macOS >= 15 [PR116809].

We have been building a legacy libgcc_s.1 DSO to support code that
was built with older compilers.

From macOS 15,  the unwinder no longer exports some of the symbols used
in that library which (a) cuases bootstrap fail and (b) means that the
legacy library is no longer useful.

No open branch of GCC emits references to this library - and any already
-built code that depends on the symbols would need rework anyway.

	PR target/116809

See https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/rs6000/t-darwin.

--- libgcc/config/rs6000/t-darwin.orig	2024-05-21 07:47:41.000000000 +0000
+++ libgcc/config/rs6000/t-darwin
@@ -56,6 +56,3 @@ unwind-dw2_s.o: HOST_LIBGCC2_CFLAGS += -
 unwind-dw2.o: HOST_LIBGCC2_CFLAGS += -maltivec
 
 LIB2ADDEH += $(srcdir)/config/rs6000/darwin-fallback.c
-
-# Build a legacy libgcc_s.1
-BUILD_LIBGCCS1 = YES


libgcc, Darwin: Drop the legacy library build for macOS >= 15 [PR116809].

We have been building a legacy libgcc_s.1 DSO to support code that
was built with older compilers.

From macOS 15,  the unwinder no longer exports some of the symbols used
in that library which (a) cuases bootstrap fail and (b) means that the
legacy library is no longer useful.

No open branch of GCC emits references to this library - and any already
-built code that depends on the symbols would need rework anyway.

	PR target/116809

See https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/t-darwin-libgccs1.

--- libgcc/config/t-darwin-libgccs1.orig	2024-12-09 03:35:09.522148209 +0000
+++ libgcc/config/t-darwin-libgccs1
@@ -0,0 +1,2 @@
+# Build a legacy libgcc_s.1
+BUILD_LIBGCCS1 = YES


libgcc, Darwin: From macOS 11, make that the earliest supported.

For libgcc, we have (so far) supported building a DSO that supports
earlier versions of the OS than the target.  From macOS 11, there are
APIs that do not exist on earlier OS versions, so limit the libgcc
range to macOS11..current.

See https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/t-darwin-min-11.

--- libgcc/config/t-darwin-min-11.orig	2024-12-10 16:14:54.471536671 +0000
+++ libgcc/config/t-darwin-min-11
@@ -0,0 +1,3 @@
+# Support building with -mmacosx-version-min back to macOS 11.
+DARWIN_MIN_LIB_VERSION = -mmacosx-version-min=11
+DARWIN_MIN_CRT_VERSION = -mmacosx-version-min=11