Compilation of OCaml 4.10.2 fails on Windows with Cygwin #29102
Description
I tried to create a switch with OCaml 4.10.2 on Windows:
opam sw create foo 4.10.2and I got the following error:
#=== ERROR while compiling ocaml-base-compiler.4.10.2 =========================#
# context 2.5.0 | win32/x86_64 | | https://opam.ocaml.org#3e41859015888fe8240e84dfc5f31bfa12a557e8
# path ~\AppData\Local\opam\roglo_legacy\.opam-switch\build\ocaml-base-compiler.4.10.2
# command ~\AppData\Local\opam\roglo_legacy\.opam-switch\build\ocaml-base-compiler.4.10.2\./configure --prefix=C:\Users\pierre\AppData\Local\opam\roglo_legacy -C
# exit-code 1
# env-file ~\AppData\Local\opam\log\ocaml-base-compiler-19304-d57f68.env
# output-file ~\AppData\Local\opam\log\ocaml-base-compiler-19304-d57f68.out
### output ###
# [...]
# checking build system type... x86_64-pc-cygwin
# checking host system type... x86_64-pc-cygwin
# checking target system type... x86_64-pc-cygwin
# checking for ld... no
# checking for link... link
# checking how to print strings... printf
# checking for gcc... no
# checking for cc... no
# checking for cl.exe... no
# configure: error: in `/cygdrive/c/Users/pierre/AppData/Local/opam/roglo_legacy/.opam-switch/build/ocaml-base-compiler.4.10.2':
# configure: error: no acceptable C compiler found in $PATH
# See `config.log' for more details
It is fresh installation with opam 2.5.0 and recent compilers work as expected.
Cygwin packages
Cygwin Package Information Package Version Status _autorebase 001091-1 OK alternatives 1.31-1 OK base-cygwin 3.8-2 OK base-files 4.3-3 OK bash 5.2.21-1 OK bzip2 1.0.8-2 OK ca-certificates 2025.2.80_v9.0.304-1 OK coreutils 9.0-1 OK crypto-policies 20190218-1 OK cygutils 1.4.17-4 OK cygwin 3.6.5-1 OK dash 0.5.12-5 OK diffutils 3.12-1 OK editrights 1.04-1 OK file 5.46-1 OK findutils 4.10.0-1 OK gawk 5.3.2-1 OK getent 2.18.90-5 OK grep 3.12-1 OK groff 1.23.0-1 OK gzip 1.14-1 OK hostname 3.13-1 OK info 7.1-2 OK ipc-utils 1.1-1 OK less 668-1 OK libargp 20250917-2 OK libattr1 2.5.2-2 OK libblkid1 2.40.2-2 OK libbz2_1 1.0.8-2 OK libcrypt2 4.5.2-1 OK libfdisk1 2.40.2-2 OK libffi6 3.2.1-2 OK libffi8 3.5.2-1 OK libgc1 8.2.10-1 OK libgcc1 13.4.0-1 OK libgdbm6 1.26-1 OK libgmp10 6.3.0-1 OK libguile3.0_1 3.0.10-3 OK libiconv2 1.17-1 OK libintl8 0.22.5-1 OK libisl23 0.27-1 OK liblastlog2 2.40.2-2 OK liblz4_1 1.9.4-1 OK liblzma5 5.8.1-1 OK libmpc3 1.3.1-1 OK libmpfr6 4.2.2-1 OK libncursesw10 6.5+20240427-1 OK libp11-kit0 0.23.20-1 OK libpcre1 8.45-1 OK libpcre2_8_0 10.47-1 OK libpipeline1 1.5.8-1 OK libpopt-common 1.19-1 OK libpopt0 1.19-1 OK libreadline7 8.2-2 OK libreadline8 8.3-1 OK libsmartcols1 2.40.2-2 OK libsqlite3_0 3.49.1-1 OK libssl1.1 1.1.1w-1 OK libssl3 3.0.18-1 OK libstdc++6 13.4.0-1 OK libtasn1_6 4.14-1 OK libuchardet0 0.0.8-1 OK libunistring5 1.2-1 OK libuuid1 2.40.2-2 OK libxxhash0 0.8.3-1 OK libzstd1 1.5.7-1 OK login 1.13-1 OK make 4.4.1-2 OK man-db 2.13.1-1 OK mingw64-i686-binutils 2.45.1-1 OK mingw64-i686-gcc-core 13.4.0-1 OK mingw64-i686-gcc-g++ 13.4.0-1 OK mingw64-i686-headers 13.0.0-1 OK mingw64-i686-runtime 13.0.0-1 OK mingw64-i686-windows-default-manifest 6.4-1 OK mingw64-i686-winpthreads 13.0.0-1 OK mingw64-x86_64-binutils 2.45.1-1 OK mingw64-x86_64-gcc-core 13.4.0-1 OK mingw64-x86_64-headers 13.0.0-1 OK mingw64-x86_64-runtime 13.0.0-1 OK mingw64-x86_64-windows-default-manifest 6.4-1 OK mingw64-x86_64-winpthreads 13.0.0-1 OK mintty 3.8.1-1 OK ncurses 6.5+20240427-1 OK openssl 3.0.18-1 OK p11-kit 0.23.20-1 OK p11-kit-trust 0.23.20-1 OK rebase 4.6.6-1 OK rsync 3.3.0-1 OK run 1.3.4-2 OK sed 4.9-1 OK tar 1.35-2 OK terminfo 6.5+20240427-1 OK tzcode 2025b-1 OK tzdata 2025b-1 OK unzip 6.0-18 OK util-linux 2.40.2-2 OK vim-minimal 9.1.1825-1 OK which 2.23-1 OK xz 5.8.1-1 OK zlib0 1.3.1-1 OK zstd 1.5.7-1 OK
I notice that your CI doesn't test new packages with old OCaml compiler on Windows:
# TODO Amend this lowerbound as older compiler packages are updated
run: opam switch set-invariant --formula "`"ocaml`" {>= `"4.13`"}"Do you have any plans to fix these packages?