clang-17, llvm-17: restore functionality on macOS 15 (Xcode 16)

This is a cherry-pick of
llvm/llvm-project@7939ce3.

Xcode 16 runs om macOS 14 and 15, so the patch is applied on macOS ≥ 14.

Closes: https://trac.macports.org/ticket/70779

lang/llvm-17/Portfile

@@ -18,7 +18,7 @@ legacysupport.use_static              yes
 legacysupport.disable_function_wrap   yes
 
 categories              lang
-platforms               {darwin > 10 < 24}
+platforms               {darwin > 10}
 license                 NCSA
 maintainers             nomaintainer
 
@@ -224,6 +224,11 @@ if {${os.platform} eq "darwin" && ${os.major} <= 16} {
     patchfiles-append 0042-mbstate_t-not-defined.patch
 }
 
+if {${os.platform} eq "darwin" && ${os.major} >= 23} {
+    # https://trac.macports.org/ticket/70779
+    patchfiles-append 0043-builtins-Move-cfi-start-s-after-the-symbol-name-NFC.patch
+}
+
 post-patch {
     reinplace "s|@@PREFIX@@|${prefix}|" \
         ${patch.dir}/clang/lib/Driver/ToolChains/Clang.cpp \

lang/llvm-17/files/0043-builtins-Move-cfi-start-s-after-the-symbol-name-NFC.patch

@@ -0,0 +1,32 @@
+From 7939ce39dac0078fef7183d6198598b99c652c88 Mon Sep 17 00:00:00 2001
+From: Jon Roelofs <[email protected]>
+Date: Fri, 17 Nov 2023 14:21:57 -0800
+Subject: [PATCH] [builtins] Move cfi start's after the symbol name [NFC]
+
+... in preparation for diagnosing improperly nested .cfi regions.
+
+See https://reviews.llvm.org/D155245
+---
+ compiler-rt/lib/builtins/assembly.h | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/compiler-rt/lib/builtins/assembly.h b/compiler-rt/lib/builtins/assembly.h
+index 169d49683f50..8c42fc773483 100644
+--- a/compiler-rt/lib/builtins/assembly.h
++++ b/compiler-rt/lib/builtins/assembly.h
+@@ -260,9 +260,10 @@
+   .globl name SEPARATOR                                                        \
+   SYMBOL_IS_FUNC(name) SEPARATOR                                               \
+   DECLARE_SYMBOL_VISIBILITY_UNMANGLED(name) SEPARATOR                          \
+-  CFI_START SEPARATOR                                                          \
+   DECLARE_FUNC_ENCODING                                                        \
+-  name: SEPARATOR BTI_C
++  name:                                                                        \
++  SEPARATOR CFI_START                                                          \
++  SEPARATOR BTI_C
+
+ #define DEFINE_COMPILERRT_FUNCTION_ALIAS(name, target)                         \
+   .globl SYMBOL_NAME(name) SEPARATOR                                           \
+-- 
+2.46.1
+