Failed to build libgcc7 in Catalina

[mengqiz]

Hi, I got the following issue when upgrading gcc7

Error: Failed to build libgcc7: command execution failed

Error: rev-upgrade failed: Error rebuilding gcc7

Please help. Thanks. There seems to be many problems in Catalina

[cjones051073 (Chris Jones)]

gcc7/libgcc7 is not (currently) supported in macOS 10.15.

Your ports cannot be up to date as you should have received the message.

Error: gcc7 7.4.0 is (currently) not supported on Darwin 19
Error: See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835 for more details
Error: Until the issue is addressed in Xcode, please instead install gcc9 / libgcc9
Error: Failed to fetch libgcc7: incompatible OS X version

Please run

sudo port sync

then follow the advice in the above message, and use gcc9 instead.

[mengqiz]

Thanks. But when I tried to install gcc9, it said that it's broken and that gcc7 & gcc8 need to be rebuilt, as following

---> Found 12 broken files, matching files to ports ---> Found 2 broken ports, determining rebuild order You can always run 'port rev-upgrade' again to fix errors. The following ports will be rebuilt:

gcc7 @7.3.0

gcc8 @8.2.0

Continue? [Y/n]:

After I keyed in Y, gcc7 still can't be installed. Any suggestions? Thanks.

[cjones051073 (Chris Jones)]

I suggest you start again following the migration instructions at

​https://trac.macports.org/wiki/Migration

as its not possible you installed gcc7 or gcc8 from scratch on macOS 10.15, they must be left over from a previous OS, meaning you failed to follow the migration instructions.

Its going to be difficult to help you with your system in this ill defined state, so you need to remove all your ports, and install them again from scratch.