The actual errors in the log are SDK related:
:info:build In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/_stdio.h:69,
:info:build from /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_lang_gcc9/gcc9/work/build/gcc/include-fixed/stdio.h:78,
:info:build from /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_lang_gcc9/gcc9/work/gcc-9.2.0/libgcc/../gcc/tsystem.h:87,
:info:build from /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_lang_gcc9/gcc9/work/gcc-9.2.0/libgcc/libgcov.h:42,
:info:build from /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_lang_gcc9/gcc9/work/gcc-9.2.0/libgcc/libgcov-merge.c:26:
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/sys/stdio.h: In function 'renameat':
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/sys/stdio.h:39:56: error: expected declaration specifiers before '__AVAILABILITY_INTERNAL__MAC_10_10'
:info:build 39 | int renameat(int, const char *, int, const char *) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_8_0);
:info:build | ^~~~~~~~~~~~~~~~~~~~~~~~
comment:ticket:59133:10 says this was fixed 2 weeks ago. You reported that you're using MacPorts 2.6.1. 2.6.2 was released a few days ago. Please run sudo port selfupdate, then try again.
