Occasional CI FTBFS

[leamas]

As seen in #79 there is occasional CI FTBFS. FWIW, my gut feeling is that it's about missing or bad cmake dependencies.

Bits and pieces from the #79 failing build:

 52%] Building CXX object libs/iso8211/CMakeFiles/ISO8211.dir/src/ddffield.cpp.o
cd /run/build/o-charts_pi/libs/iso8211 && /usr/bin/c++ -DWXUSINGDLL -D_FILE_OFFSET_BITS=64 -D__OCPN_USE_GLEW__ -D__WXGTK3__ -D__WXGTK__ -DocpnUSE_GL -DocpnUSE_GLSL -I/run/build/o-charts_pi/include -I/app/extensions/o-charts_pi/include -I/run/build/o-charts_pi/libs/iso8211/src -I/run/build/o-charts_pi/libs/cpl/src -isystem /app/lib/wx/include/gtk3-unicode-3.2 -isystem /app/include/wx-3.2 -O2 -pipe -g -Wp,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer  -DFLATPAK -O3  -Wall -Wno-unused-result -fexceptions -DwxABI_VERSION=30202 -O3 -DNDEBUG -std=c++17 -fPIC -fvisibility=hidden -MD -MT libs/iso8211/CMakeFiles/ISO8211.dir/src/ddffield.cpp.o -MF CMakeFiles/ISO8211.dir/src/ddffield.cpp.o.d -o CMakeFiles/ISO8211.dir/src/ddffield.cpp.o -c /run/build/o-charts_pi/libs/iso8211/src/ddffield.cpp
/usr/bin/make  -f libs/iso8211/CMakeFiles/ISO8211.dir/build.make libs/iso8211/CMakeFiles/ISO8211.dir/depend
make[6]: Entering directory '/run/build/o-charts_pi'
cd /run/build/o-charts_pi && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /run/build/o-charts_pi /run/build/o-charts_pi/libs/iso8211 /run/build/o-charts_pi /run/build/o-charts_pi/libs/iso8211 /run/build/o-charts_pi/libs/iso8211/CMakeFiles/ISO8211.dir/DependInfo.cmake "--color="
Dependencies file "libs/iso8211/CMakeFiles/ISO8211.dir/src/ddffield.cpp.o.d" is newer than depends file "/run/build/o-charts_pi/libs/iso8211/CMakeFiles/ISO8211.dir/compiler_depend.internal".
Consolidate compiler generated dependencies of target ISO8211
make[6]: Leaving directory '/run/build/o-charts_pi'

and finally

[ 58%] Linking CXX static library libISO8211.a
cd /run/build/o-charts_pi/libs/iso8211 && /usr/bin/cmake -P CMakeFiles/ISO8211.dir/cmake_clean_target.cmake
cd /run/build/o-charts_pi/libs/iso8211 && /usr/bin/cmake -E cmake_link_script CMakeFiles/ISO8211.dir/link.txt --verbose=1
cd /run/build/o-charts_pi/libs/iso8211 && /usr/bin/cmake -E cmake_link_script CMakeFiles/ISO8211.dir/link.txt --verbose=1
/usr/bin/ar: libISO8211.a: error reading ddffield.cpp.o: file truncated
/usr/bin/ar qc libISO8211.a CMakeFiles/ISO8211.dir/src/ddffield.cpp.o CMakeFiles/ISO8211.dir/src/ddfsubfielddefn.cpp.o CMakeFiles/ISO8211.dir/src/ddffielddefn.cpp.o CMakeFiles/ISO8211.dir/src/ddfmodule.cpp.o CMakeFiles/ISO8211.dir/src/ddfrecord.cpp.o CMakeFiles/ISO8211.dir/src/ddfutils.cpp.o
make[6]: *** [libs/iso8211/CMakeFiles/ISO8211.dir/build.make:184: libs/iso8211/libISO8211.a] Error 1
make[6]: *** Deleting file 'libs/iso8211/libISO8211.a

EDIT: Better Englisch, update last log snippet