Add new distributions where fpm is available to README (#562)

- MSYS2 has now a MinGW package for fpm
- Spack has now a package for fpm

Author: awvwgk

README.md

@@ -38,9 +38,10 @@ __Note:__ On Linux and MacOS, you will need to enable executable permission befo
 
 _e.g._ `$ chmod u+x fpm-0.4.0-linux-x86_64`
 
-#### Conda
 
-Fpm is available on conda-forge, to add conda-forge to your channels use:
+#### [Conda]
+
+Fpm is available on [conda-forge], to add conda-forge to your channels use:
 
 ```
 conda config --add channels conda-forge
@@ -56,6 +57,47 @@ conda activate fpm
 The conda package manager can be installed from [miniforge](https://github.com/conda-forge/miniforge/releases)
 or from [miniconda](https://docs.conda.io/en/latest/miniconda.html).
 
+[Conda]: https://conda.io
+[conda-forge]: https://conda-forge.org/
+
+
+#### [MSYS2]
+
+Fpm is available as MinGW package in the MSYS2 package manager.
+To install fpm with pacman use
+
+```
+pacman -S mingw-w64-x86_64-fpm
+```
+
+Afterwards fpm will be available for usage.
+Currently `i686`, `x86_64` and `ucrt-x86_64` are supported MinGW architectures for fpm.
+For more details check the package information [here](https://packages.msys2.org/base/mingw-w64-fpm).
+
+[MSYS2]: https://www.msys2.org/
+
+
+#### [Spack]
+
+Fpm is available with spack in its develop version.
+To install fpm from spack use
+
+```
+spack install fpm
+```
+
+You can add `+openmp` to enable parallelization of the target compilation in fpm.
+To use fpm in your environment load it with
+
+```
+spack load fpm
+```
+
+For more details check the package information [here](https://spack.readthedocs.io/en/latest/package_list.html#fpm).
+
+[Spack]: https://spack.io
+
+
 #### Github Actions
 
 To setup *fpm* within Github actions for automated testing, you can use the [fortran-lang/setup-fpm](https://github.com/marketplace/actions/setup-fpm) action.