[bug] Cross compiling with MinGW fails

When cross compiling from Linux to Windows using MinGw Conan tries to use cmake -G "MinGW Makefiles" but CMake MinGW generator isn’t available on Linux.

It worked fine until yesterday (12/8/2022).

Environment Details (include every applicable attribute)

• Operating System+version: Manjaro Linux, Ubuntu 22.04
• Compiler+version: MinGW GCC 12.1, MinGW GCC 10
• Conan version: 1.51.2, 1.50.0, 1.47.0
• Python version: 3.10.5, 3.10.4

Steps to reproduce (Include if Applicable)

add MinGW profile:

toolchain=/usr/x86_64-w64-mingw32 # Adjust this path
target_host=x86_64-w64-mingw32
cc_compiler=gcc
cxx_compiler=g++

[env]
CONAN_CMAKE_FIND_ROOT_PATH=$toolchain  # Optional, for CMake to find things in that folder
CONAN_CMAKE_SYSROOT=$toolchain  # Optional, if we want to define sysroot
CHOST=$target_host
AR=$target_host-ar
AS=$target_host-as
RANLIB=$target_host-ranlib
CC=$target_host-$cc_compiler
CXX=$target_host-$cxx_compiler
STRIP=$target_host-strip
RC=$target_host-windres

[settings]
# We are cross-building to Windows
os=Windows
arch=x86_64
compiler=gcc

# Adjust to the gcc version of your MinGW package
compiler.version=11
compiler.libcxx=libstdc++11
build_type=Release

create conanfile.txt with a package that fails

libraries that fail to build (for me fmt, glfw and boost failed):

[requires]
fmt/9.0.0

try conan install it with the MinGW profile: conan install . --build=outdated -pr=mingw

get the following error:

Configuration:
[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.libcxx=libstdc++11
compiler.version=11
os=Windows
[options]
[build_requires]
[env]
AR=x86_64-w64-mingw32-ar
AS=x86_64-w64-mingw32-as
CC=x86_64-w64-mingw32-gcc
CHOST=x86_64-w64-mingw32
CONAN_CMAKE_FIND_ROOT_PATH=/usr/x86_64-w64-mingw32 # Adjust this path  # Optional, for CMake to find things in that folder
CONAN_CMAKE_SYSROOT=/usr/x86_64-w64-mingw32 # Adjust this path  # Optional, if we want to define sysroot
CXX=x86_64-w64-mingw32-g++
RANLIB=x86_64-w64-mingw32-ranlib
RC=x86_64-w64-mingw32-windres
STRIP=x86_64-w64-mingw32-strip
fmt/9.0.0: WARN: Package binary is corrupted, removing: a054a3505f46390899b536d8af712e4a80b781a7
conanfile.txt: Installing package
Requirements
    fmt/9.0.0 from 'conancenter' - Cache
Packages
    fmt/9.0.0:a054a3505f46390899b536d8af712e4a80b781a7 - Build

Cross-build from 'Linux:x86_64' to 'Windows:x86_64'
Installing (downloading, building) binaries...
fmt/9.0.0: WARN: Build folder is dirty, removing it: /home/vm/.conan/data/fmt/9.0.0/_/_/build/a054a3505f46390899b536d8af712e4a80b781a7
fmt/9.0.0: Copying sources to build folder
fmt/9.0.0: Building your package in /home/vm/.conan/data/fmt/9.0.0/_/_/build/a054a3505f46390899b536d8af712e4a80b781a7
fmt/9.0.0: Generator txt created conanbuildinfo.txt
fmt/9.0.0: Calling generate()
fmt/9.0.0: WARN: Using the new toolchains and generators without specifying a build profile (e.g: -pr:b=default) is discouraged and might cause failures and unexpected behavior
fmt/9.0.0: Aggregating env generators
fmt/9.0.0: Calling build()
fmt/9.0.0: CMake command: cmake -G "MinGW Makefiles" -DCMAKE_TOOLCHAIN_FILE="/home/vm/.conan/data/fmt/9.0.0/_/_/build/a054a3505f46390899b536d8af712e4a80b781a7/build/generators/conan_toolchain.cmake" -DCMAKE_INSTALL_PREFIX="/home/vm/.conan/data/fmt/9.0.0/_/_/package/a054a3505f46390899b536d8af712e4a80b781a7" -DCMAKE_POLICY_DEFAULT_CMP0091="NEW" -DCMAKE_BUILD_TYPE="Release" -DFMT_DOC="False" -DFMT_TEST="False" -DFMT_INSTALL="True" -DFMT_LIB_DIR="lib" -DFMT_OS="True" "/home/vm/.conan/data/fmt/9.0.0/_/_/build/a054a3505f46390899b536d8af712e4a80b781a7/."
CMake Error: Could not create named generator MinGW Makefiles

Generators
  Green Hills MULTI            = Generates Green Hills MULTI files
                                 (experimental, work-in-progress).
* Unix Makefiles               = Generates standard UNIX makefiles.
  Ninja                        = Generates build.ninja files.
  Ninja Multi-Config           = Generates build-<Config>.ninja files.
  Watcom WMake                 = Generates Watcom WMake makefiles.
  CodeBlocks - Ninja           = Generates CodeBlocks project files.
  CodeBlocks - Unix Makefiles  = Generates CodeBlocks project files.
  CodeLite - Ninja             = Generates CodeLite project files.
  CodeLite - Unix Makefiles    = Generates CodeLite project files.
  Eclipse CDT4 - Ninja         = Generates Eclipse CDT 4.0 project files.
  Eclipse CDT4 - Unix Makefiles= Generates Eclipse CDT 4.0 project files.
  Kate - Ninja                 = Generates Kate project files.
  Kate - Unix Makefiles        = Generates Kate project files.
  Sublime Text 2 - Ninja       = Generates Sublime Text 2 project files.
  Sublime Text 2 - Unix Makefiles
                               = Generates Sublime Text 2 project files.

fmt/9.0.0: 
fmt/9.0.0: ERROR: Package 'a054a3505f46390899b536d8af712e4a80b781a7' build failed
fmt/9.0.0: WARN: Build folder /home/vm/.conan/data/fmt/9.0.0/_/_/build/a054a3505f46390899b536d8af712e4a80b781a7/build/Release
ERROR: fmt/9.0.0: Error in build() method, line 89
	cmake.configure(variables=cache_entries)
	ConanException: Error 1 while executing cmake -G "MinGW Makefiles" -DCMAKE_TOOLCHAIN_FILE="/home/vm/.conan/data/fmt/9.0.0/_/_/build/a054a3505f46390899b536d8af712e4a80b781a7/build/generators/conan_toolchain.cmake" -DCMAKE_INSTALL_PREFIX="/home/vm/.conan/data/fmt/9.0.0/_/_/package/a054a3505f46390899b536d8af712e4a80b781a7" -DCMAKE_POLICY_DEFAULT_CMP0091="NEW" -DCMAKE_BUILD_TYPE="Release" -DFMT_DOC="False" -DFMT_TEST="False" -DFMT_INSTALL="True" -DFMT_LIB_DIR="lib" -DFMT_OS="True" "/home/vm/.conan/data/fmt/9.0.0/_/_/build/a054a3505f46390899b536d8af712e4a80b781a7/."

[Enhex]

yeah using two profiles with -pr:b=default -pr:h=linux_to_win64 works

[JackCarterSmith]

Same problem in there with zlib cross-building Linux->Windows using MinGW 9.3

yeah using two profiles with -pr:b=default -pr:h=linux_to_win64 works

This 2 profiles methods work, I can confirm. Set default as the auto-generated conan config for the “real” host and linux_to_win64 as the target system (aka. Windows with MinGW)