I get what your saying, but why can I only get GCC 7.4.x from TigerPorts/LeopardPorts? Something else is going on, the GCC 7 compiler is only 4 years old as of 2021 (which is literally insane for this platform to have that power)...
gcc 7.5.0 has a bit of a show-stopper bug in it, wherein software randomly will crash due to an ABI difference between libstdc++ from gcc 7.5.0 and the one from the 10.4 and 10.4 system. The issue is technically called an ODR violation.
It happens intermittently -- building cmake for example -- and then randomly not for another build. It happens on both PPC and Intel.
We discussed it on MacPorts -- one option was to hold gcc7 back at 7.4.x, which did not exhibit the issue. The other was to press on to gcc7 7.5.x and let the chips fall as they may. The group decision was to do the latter. An attempt was made to work around the issue using DYLD_LIBRARY_PATH, which does work, if you can catch each and every invocation where it is needed.
As there is no visible improvement in gcc7 7.5.x compared to gcc7 7.4.x that I could see, no new features that were helpful, no new software that would build with gcc 7.5.0 that would not build with gcc 7.4.x -- I decided to hang back myself and use gcc 7.4.x until upstream fixes this.
Upstream has been working on it. gcc 9.x and gcc 10.x both will build and install on Tiger, and although they do not yet have the ODR fix in them, they are the most likely to get it.
Once that happens, my plan is to bump MacPorts to use that (libgcc 10 on Tiger) and then hopefully I can retire gcc 7.4.0 forever.
Regarding TigerPorts / LeopardPorts:
I've been building software on Tiger and Leopard for many years with MacPorts. I have many many thousands of ports installed in both, and I try to keep all of them as current as possible.
I came up the a compatibility library that MacPorts uses to help keep older systems going, and that was picked up by others as well and is enthusiastically supported now. I maintain the cctools port, and the ld64 port, and the clang ports and try to keep these working well on all the systems. The current cctools port works all the way back to Tiger, for example. clang-7.0 will install on Tiger Intel (with skills, not just "sudo port install clang-7.0" on Tiger), and it is not too far from working on Leopard PPC.
When something doesn't update on MacPorts during a "port upgrade" run, and something often doesn't update (this is Tiger we're talking about, after all) I can usually spot the needed fix in a minute or two. It's often the same collection of fixes, wearing different clothing.
I fix them, push the fixes to my TigerPorts/LeopardPorts repo so I don't forget what I did, and move on until the whole tree has been updated.
Then later, I look at the fixes I have done, and I try to see which ones will or will not be accepted into the main MacPorts repo. The ones that I think might be accepted, I either push or open a PR for. Some are more contentious, requiring a package to be held back from upgrading perhaps (eg libsdl2) or other more major surgery. There is limit to the amount of conditionalization that is tolerable in a Portfile.
The ones that I either can't sell to MacPorts, or I don't believe can be sold, I keep in Tiger/LeopardPorts until things seem ripe perhaps to upstream them.
I would invite everyone on this thread to be active in MacPorts if you would like the (already very good) Tiger/Leopard support to stay current. Ryan, who manages MacPorts, has a Leopard PPC buildbot -- just has not brought it online for some reason -- and has Tiger machines as well. I think to a certain extent they are looking to see how much enthusiasm there is to keep that support ongoing.
Your interest, comments, and in particular patches and fixes will be most appreciated!
