Add ASIO as 3rdparty dependency (#13)

Author: nilssonk

3rdparty/CMakeLists.txt

@@ -1,2 +1,3 @@
+add_subdirectory(asio)
 add_subdirectory(fmt)
 add_subdirectory(libvips)

3rdparty/asio/CMakeLists.txt

@@ -0,0 +1,22 @@
+include(FetchContent)
+FetchContent_Declare(
+    asio_fetch
+    GIT_REPOSITORY https://github.com/chriskohlhoff/asio
+    GIT_TAG asio-1-24-0
+    GIT_SHALLOW TRUE
+)
+FetchContent_GetProperties(asio_fetch)
+if(NOT asio_fetch_POPULATED)
+    FetchContent_Populate(asio_fetch)
+
+    add_library(asio INTERFACE)
+    target_include_directories(asio SYSTEM INTERFACE ${asio_fetch_SOURCE_DIR}/asio/include)
+    target_compile_definitions(asio
+        INTERFACE
+        ASIO_DISABLE_VISIBILITY
+        ASIO_NO_DEPRECATED
+        ASIO_NO_DYNAMIC_BUFFER_V1
+        ASIO_NO_TS_EXECUTORS
+        ASIO_NO_TYPEID
+        ASIO_STANDALONE)
+endif()

README.md

@@ -6,12 +6,15 @@ A tool for performing black and white Bayer dithering, written in C++17.
 ![GCC Build](https://github.com/nilssonk/vulkan-cpp/actions/workflows/gcc-build.yml/badge.svg)
 
 ### 2x2 Bayer Kernel
+
 ![Dither 2x2 Kernel](.github/img/dither2.jpg)
 
 ### 4x4 Bayer Kernel
+
 ![Dither 4x4 Kernel](.github/img/dither4.jpg)
 
 ### 8x8 Bayer Kernel
+
 ![Dither 8x8 Kernel](.github/img/dither8.jpg)
 
 ## Usage
@@ -30,6 +33,8 @@ There are a few dependencies required to build this tool:
 
 #### Bundled/Fetched by CMake
 
+-   ASIO (https://think-async.com/Asio)
+
 -   fmt (https://github.com/fmtlib/fmt)
 
 #### Not included