Problem downloading GMP using MacPorts, need advice

Hans Åberg haberg-1 at
Wed Jul 20 23:05:20 CEST 2022

> On 14 Jul 2022, at 08:25, Jay Freeman <jay_reynolds_freeman at> wrote:
> I am trying to download GMP via MacPorts; I am a stranger to both, and am having a problem. I thought I would ask about it here first, though of course it may be a problem with my use of MacPorts, but the problem seems at first sight to be a dependency required by the GMP download itself.
> I am running MacOS 11.6.5 (Big Sur) on a 2019 Mac Pro with Intel hardware. I have Xcode 13.2.1 installed, and have installed the associated command-line tools. I downloaded the MacPorts distribution for Big Sur and ran an apparently clean install via the installer. After some searching, I tried: "sudo port install gmp" and got the following:
> #### SNIP ####
>> sudo port install gmp                             
> Password:
> --->  Cleaning gmp
> --->  Scanning binaries for linking errors
> --->  Found 12 broken files, matching files to ports
> Warning: No port llvm-3.0 found in the index; can't rebuild
> --->  Found 1 broken port, determining rebuild order
> You can always run 'port rev-upgrade' again to fix errors.
> The following ports will be rebuilt: gcc46 @4.6.3
> Continue? [Y/n]: Y 
> --->  Fetching distfiles for gcc46
> Error: building gcc46 is not supported with Xcode 9 or greater
> Error: Failed to fetch gcc46: unsupported platform

> Any advice? If you folks think this is a MacPorts issue, I will try them next.

Update to MacOS 12.4 if you can, and then MacPorts. I think that gcc46 was the last real GCC that Xcode supported, replaced by Apple's inhouse Clang.

The link below shows that gmp depends on clang-13, but also that is too old, as there is clang-14 now. MacPorts also has gcc12.

So one way is to install those compilers, if one wants something more up to date, and make a soft link in /use/local/bin/ from gcc to the one preferred, and then make a standard install from the sources at GMP probably prefers GCC over Clang.

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