[MacPorts] #72597: libgcc14 fails to build on macOS 16 (Darwin 26): conflicting types for MPG_PAYLOAD in <mach/port.h>

[MacPorts]

#72597: libgcc14 fails to build on macOS 16 (Darwin 26): conflicting types for
MPG_PAYLOAD in <mach/port.h>
-----------------------+----------------------
 Reporter:  Frozaccio  |      Owner:  (none)
     Type:  defect     |     Status:  new
 Priority:  Normal     |  Milestone:
Component:  ports      |    Version:  2.10.7
 Keywords:             |       Port:  libgcc14
-----------------------+----------------------
 Trying to build `libgcc14` (required by `gcc14`) on macOS 16 (Darwin 26 /
 macOS "Tahoe") fails during compilation due to multiple conflicting
 definitions of `MPG_PAYLOAD` found in the system SDK's
 `/usr/include/mach/port.h`.

 The error log includes:

 :info:build
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/mach/port.h:523:1:
 error: conflicting types for 'MPG_PAYLOAD'; have 'uint64_t(uint8_t,
 uint32_t,  uint16_t,  uint16_t)'
 :info:build
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/mach/port.h:498:1:
 note: previous definition of 'MPG_PAYLOAD' with type 'uint64_t(uint8_t,
 uint32_t)'

 This happens repeatedly for different overloads of `MPG_PAYLOAD`, e.g.:

 - `MPG_PAYLOAD(uint8_t, uint32_t)`
 - `MPG_PAYLOAD(uint8_t, uint32_t, uint32_t)`
 - `MPG_PAYLOAD(uint8_t, uint32_t, uint16_t, uint16_t)`

 **System Details**:

 - macOS 16.0 (Darwin 26.0.0, "Tahoe")
 - Xcode 16.4 (Build 16F6), SDK:
 `/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk`
 - MacPorts base version: 2.10.7
 - Command: `sudo port install libgcc14`

 This appears to be a change in the macOS 16 SDK headers that GCC 14.2.0
 (and its startup CRT objects) does not expect.

 **Workaround attempts**:
 - Confirmed headers exist in correct SDK path
 - Tried reinstalling Xcode and CLT
 - Attempted clean build via `sudo port clean libgcc14`
 - gcc13 fails too due to same dependency on `libgcc14`

 Please advise if a workaround or upstream patch is available. I'm happy to
 test or help isolate the issue further.

-- 
Ticket URL: <https://trac.macports.org/ticket/72597>
MacPorts <https://www.macports.org/>
Ports system for macOS