sys-devel/gcc-12.1.0: patch to fix macOS 13 build.

When bootstrapping Gentoo Prefix on macOS 13.2 (Ventura) on
an Apple M1 system, it will fail at stage2 due to a GCC build
failure because GCC 12.1 is incompatible with macOS 13.

make[2]: Entering directory '/Users/apple/gentoo/tmp/var/tmp/portage/sys-devel/gcc-12.1.0/work/build/gcc'
/Users/apple/Gentoo/tmp/var/tmp/portage/sys-devel/gcc-12.1.0/work/build/./gcc/xgcc -B/Users/apple/Gentoo/tmp/var/tmp/portage/sys-devel/g
cc-12.1.0/work/build/./gcc/ -xc++ -nostdinc /dev/null -S -o /dev/null -fself-test=/Users/apple/Gentoo/tmp/var/tmp/portage/sys-devel/gcc-
12.1.0/work/gcc-12-branch-gcc-12.1-darwin-r0/gcc/testsuite/selftests
<built-in>: error: unknown value '13.0' of '-mmacosx-version-min'

This problem can be fixed by applying the upstream patch

* Darwin: Future-proof -mmacosx-version-min
> f18cbc1ee1f4 (2021-12-18) updated various parts of gcc to not impose a
> Darwin or macOS version maximum of the current known release. [...] However,
> f18cbc1ee1f4 missed config/darwin-c.c (now .cc), which continued to impose a
> maximum of macOS 12 on the -mmacosx-version-min compiler driver argument.
https://github.com/gcc-mirror/gcc/commit/6725f186cb70d48338f69456864bf469a12ee5be.patch

However, there's another separate name collision bug in fs_path.h of
libstdc++ that will produce another error, similar to the following
(I lost the original logs, this is copied from an issue I found online).

In file included from /private/tmp/gccA10-20221211-4993-1miwm67/gcc-10.4.0/build/x86_64-apple-darwin22/libstdc++-v3/include/filesystem:45,
                 from ../../../../../libstdc++-v3/src/c++17/fs_dir.cc:30:
/private/tmp/gccA10-20221211-4993-1miwm67/gcc-10.4.0/build/x86_64-apple-darwin22/libstdc++-v3/include/bits/fs_path.h:133:30: error: abstract declarator 'std::filesystem::__cxx11::__detail::<unnamed struct>' used as declaration
  133 |   struct __null_terminated { };

To fix this problem, the following upstream patch must be applied:

* libstdc++: Rename __null_terminated to avoid collision with Apple SDK
> The macOS 13 SDK (and equivalent-version iOS and other Apple OS SDKs)
> contain this definition in <sys/cdefs.h>: "#define __null_terminated" This
> collides with the use of __null_terminated in libstdc++'s experimental
> fs_path.h.
https://github.com/gcc-mirror/gcc/commit/d1201dbf55a11d391030914985ba6b443e59baa5.patch

Fixing both problems allow successful compile of sys-devel/gcc-12.1.0 in
stage2 and stage3.

This commit fixes Gentoo bug 895332 [1].

Note that sys-devel/gcc-12.2.0 has its own bugs (Gentoo bug 895334) that
prevents bootstrapping from happening. My recommendation is fixing
sys-devel/gcc-12.1.0 for now, and masking sys-devel/gcc-12.2.0 until the
problem has been thoroughly investigated.

Closes: https://bugs.gentoo.org/895332
Signed-off-by: Yifeng Li <tomli@tomli.me>
Closes: https://github.com/gentoo/prefix/pull/17
Signed-off-by: Sam James <sam@gentoo.org>

3 files changed, 143 insertions, 0 deletions

diff --git a/sys-devel/gcc/files/gcc-12.1.0-avoid-null-terminated-name-collision-with-macos-13-sdk.patch b/sys-devel/gcc/files/gcc-12.1.0-avoid-null-terminated-name-collision-with-macos-13-sdk.patch
new file mode 100644
index 0000000000..1abfae345c
--- /dev/null
+++ b/sys-devel/gcc/files/gcc-12.1.0-avoid-null-terminated-name-collision-with-macos-13-sdk.patch
@@ -0,0 +1,85 @@
+https://bugs.gentoo.org/886491
+https://bugs.gentoo.org/895332
+https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d1201dbf55a11d391030914985ba6b443e59baa5
+
+From d1201dbf55a11d391030914985ba6b443e59baa5 Mon Sep 17 00:00:00 2001
+From: Mark Mentovai <mark@mentovai.com>
+Date: Mon, 13 Jun 2022 16:40:19 +0100
+Subject: [PATCH] libstdc++: Rename __null_terminated to avoid collision with
+ Apple SDK
+
+The macOS 13 SDK (and equivalent-version iOS and other Apple OS SDKs)
+contain this definition in <sys/cdefs.h>:
+
+863  #define __null_terminated
+
+This collides with the use of __null_terminated in libstdc++'s
+experimental fs_path.h.
+
+As libstdc++'s use of this token is entirely internal to fs_path.h, the
+simplest workaround, renaming it, is most appropriate. Here, it's
+renamed to __nul_terminated, referencing the NUL ('\0') value that is
+used to terminate the strings in the context in which this tag structure
+is used.
+
+libstdc++-v3/ChangeLog:
+
+	* include/experimental/bits/fs_path.h (__detail::__null_terminated):
+	Rename to __nul_terminated to avoid colliding with a macro in
+	Apple's SDK.
+
+Signed-off-by: Mark Mentovai <mark@mentovai.com>
+(cherry picked from commit 254e88b3d7e8abcc236be3451609834371cf4d5d)
+---
+ libstdc++-v3/include/experimental/bits/fs_path.h | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/libstdc++-v3/include/experimental/bits/fs_path.h b/libstdc++-v3/include/experimental/bits/fs_path.h
+index b0825ba76e80..19d246100cb5 100644
+--- a/libstdc++-v3/include/experimental/bits/fs_path.h
++++ b/libstdc++-v3/include/experimental/bits/fs_path.h
+@@ -140,10 +140,10 @@ namespace __detail
+     inline _Source
+     _S_range_begin(_Source __begin) { return __begin; }
+ 
+-  struct __null_terminated { };
++  struct __nul_terminated { };
+ 
+   template<typename _Source>
+-    inline __null_terminated
++    inline __nul_terminated
+     _S_range_end(_Source) { return {}; }
+ 
+   template<typename _CharT, typename _Traits, typename _Alloc>
+@@ -459,11 +459,11 @@ namespace __detail
+       struct _Cvt;
+ 
+     static string_type
+-    _S_convert(value_type* __src, __detail::__null_terminated)
++    _S_convert(value_type* __src, __detail::__nul_terminated)
+     { return string_type(__src); }
+ 
+     static string_type
+-    _S_convert(const value_type* __src, __detail::__null_terminated)
++    _S_convert(const value_type* __src, __detail::__nul_terminated)
+     { return string_type(__src); }
+ 
+     template<typename _Iter>
+@@ -477,7 +477,7 @@ namespace __detail
+ 
+     template<typename _InputIterator>
+       static string_type
+-      _S_convert(_InputIterator __src, __detail::__null_terminated)
++      _S_convert(_InputIterator __src, __detail::__nul_terminated)
+       {
+ 	auto __s = _S_string_from_iter(__src);
+ 	return _S_convert(__s.c_str(), __s.c_str() + __s.size());
+@@ -504,7 +504,7 @@ namespace __detail
+ 
+     template<typename _InputIterator>
+       static string_type
+-      _S_convert_loc(_InputIterator __src, __detail::__null_terminated,
++      _S_convert_loc(_InputIterator __src, __detail::__nul_terminated,
+ 		     const std::locale& __loc)
+       {
+ 	const std::string __s = _S_string_from_iter(__src);
diff --git a/sys-devel/gcc/files/gcc-12.1.0-recognize-mmacosx-version-min-13.0-and-newer.patch b/sys-devel/gcc/files/gcc-12.1.0-recognize-mmacosx-version-min-13.0-and-newer.patch
new file mode 100644
index 0000000000..f5c32d886c
--- /dev/null
+++ b/sys-devel/gcc/files/gcc-12.1.0-recognize-mmacosx-version-min-13.0-and-newer.patch
@@ -0,0 +1,54 @@
+https://bugs.gentoo.org/886491
+https://bugs.gentoo.org/895332
+https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=6725f186cb70d48338f69456864bf469a12ee5be
+
+From 6725f186cb70d48338f69456864bf469a12ee5be Mon Sep 17 00:00:00 2001
+From: Mark Mentovai <mark@mentovai.com>
+Date: Fri, 10 Jun 2022 15:56:42 +0100
+Subject: [PATCH] Darwin: Future-proof -mmacosx-version-min
+
+f18cbc1ee1f4 (2021-12-18) updated various parts of gcc to not impose a
+Darwin or macOS version maximum of the current known release. Different
+parts of gcc accept, variously, Darwin version numbers matching
+darwin2*, and macOS major version numbers up to 99. The current released
+version is Darwin 21 and macOS 12, with Darwin 22 and macOS 13 expected
+for public release later this year. With one major OS release per year,
+this strategy is expected to provide another 8 years of headroom.
+
+However, f18cbc1ee1f4 missed config/darwin-c.c (now .cc), which
+continued to impose a maximum of macOS 12 on the -mmacosx-version-min
+compiler driver argument. This was last updated from 11 to 12 in
+11b967577483 (2021-10-27), but kicking the can down the road one year at
+a time is not a viable strategy, and is not in line with the more recent
+technique from f18cbc1ee1f4.
+
+Prior to 556ab5125912 (2020-11-06), config/darwin-c.c did not impose a
+maximum that needed annual maintenance, as at that point, all macOS
+releases had used a major version of 10. The stricter approach imposed
+since then was valuable for a time until the particulars of the new
+versioning scheme were established and understood, but now that they
+are, it's prudent to restore a more permissive approach.
+
+gcc/ChangeLog:
+
+	* config/darwin-c.cc: Make -mmacosx-version-min more future-proof.
+
+Signed-off-by: Mark Mentovai <mark@mentovai.com>
+---
+ gcc/config/darwin-c.cc | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/gcc/config/darwin-c.cc b/gcc/config/darwin-c.cc
+index 9203c84d2c26c..1f82b36d2de10 100644
+--- a/gcc/config/darwin-c.cc
++++ b/gcc/config/darwin-c.cc
+@@ -691,7 +691,8 @@ macosx_version_as_macro (void)
+   if (!version_array)
+     goto fail;
+ 
+-  if (version_array[MAJOR] < 10 || version_array[MAJOR] > 12)
++  /* System tools accept up to 99 as a major version.  */
++  if (version_array[MAJOR] < 10 || version_array[MAJOR] > 99)
+     goto fail;
+ 
+   if (version_array[MAJOR] == 10 && version_array[MINOR] < 10)
diff --git a/sys-devel/gcc/gcc-12.1.0.ebuild b/sys-devel/gcc/gcc-12.1.0.ebuild
index 590c202d8c..9b85f3d9aa 100644
--- a/sys-devel/gcc/gcc-12.1.0.ebuild
+++ b/sys-devel/gcc/gcc-12.1.0.ebuild
@@ -45,6 +45,10 @@ src_prepare() {
 
 	eapply_user
 
+	# fix build for macOS 13 Ventura
+	eapply "${FILESDIR}"/gcc-12.1.0-recognize-mmacosx-version-min-13.0-and-newer.patch
+	eapply "${FILESDIR}"/gcc-12.1.0-avoid-null-terminated-name-collision-with-macos-13-sdk.patch
+
 	# make sure 64-bits native targets don't screw up the linker paths
 	eapply "${FILESDIR}"/gcc-12-no-libs-for-startfile.patch
 	if use prefix; then