Write Haiku build instruction

docs/INSTALL.MD

@@ -207,3 +207,14 @@ to reduce used disk space via not downloading entire git history.
 6. Enter build directory using `cd build`.
 7. Generate build files using `cmake ..`. You may want to add additional arguments to CMake, see *`CMakeLists.txt` documentation* section.
 8. Build project using `make -j$(nproc)`.
+
+### Haiku
+1. Install required tools: `pkgman install cmake`.
+2. Clone repository with following command: `git clone https://git.cubesoftware.xyz/PolyGun/PolyGun.git`. You can add `--depth=1` argument
+to reduce used disk space via not downloading entire git history.
+3. Install required libraries. Libraries may vary depending on what build configuration you will use. This tutorial assumes full build.
+   `pkgman install openal_devel vorbis_devel png_devel freetype_devel`. `ogg_devel` and `zlib_devel` will be installed automatically.
+4. Make build directory using `mkdir build`.
+5. Enter build directory using `cd build`.
+6. Generate build files using `cmake ..`.
+7. Build project using `make -j$(nproc)`.

readme.md

@@ -23,6 +23,7 @@ PolyGun comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable
 a C++ 17 compiler on there)
 - FreeBSD (X11 and Wayland windowing systems)
 - SerenityOS
+- Haiku
 
 ## Contributing
 ### See [docs/CODING_STYLE.MD](docs/CODING_STYLE.MD)