The ARMv7 CI job seems to be failing non-deterministically during `configure`. For instance, see https://gitlab.haskell.org/ghc/ghc/-/jobs/353311. I have managed to reproduce the issue. The difference seems to stem from whether `configure` chooses to use `ld.lld` as the linker, which seems to be oddly non-deterministic. # Passing case For instance, when things are passing we get: ``` checking for -ld.lld... no checking for ld.lld... ld.lld checking whether C compiler supports -fuse-ld=lld... no configure: unable to convince 'cc' to use linker 'ld.lld' checking for -ld.gold... no checking for ld.gold... ld.gold checking whether C compiler supports -fuse-ld=gold... yes checking for -readelf... no checking for readelf... readelf checking for -as... no checking for as... as checking for ld bug 16177... unaffected checking whether ld is GNU ld... YES checking whether ld understands --build-id... yes checking whether ld understands -no_compact_unwind... yes checking whether ld understands -filelist... no checking for -nm... no ``` # Failing case However, when things fail we instead get: ``` checking for -ld.lld... no checking for ld.lld... ld.lld checking whether C compiler supports -fuse-ld=lld... yes checking for -readelf... no checking for readelf... readelf checking for -as... no checking for as... as checking for ld bug 16177... ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected unaffected checking whether ld is GNU ld... YES checking whether ld understands --build-id... yes checking whether ld understands -no_compact_unwind... no checking whether ld understands -filelist... no checking for -nm... no ``` and later we get: ``` checking for char... yes checking alignment of char... configure: error: cannot compute alignment (char) See `config.log' for more details. ./configure --enable-tarballs-autodownload GHC=/usr/local/bin/ghc HAPPY=/home/ghc/.cabal/bin/happy ALEX=/home/ghc/.cabal/bin/alex faile ``` The output in `config.log` is: ``` configure:12135: checking alignment of char configure:12141: cc -o conftest -g -O2 -fuse-ld=lld -marm -Wl,-z,noexecstack conftest.c >&5 collect2: fatal error: ld terminated with signal 6 [Aborted], core dumped compilation terminated. terminate called after throwing an instance of 'std::system_error' what(): Resource temporarily unavailable configure:12141: $? = 1 configure: program exited with status 1 configure: failed program was: ... ```