Update CMakeLists.txt to support conan

This update allows for users of the conan package manager to build the project. Tested on Linux with conan 1.44.

CMakeLists.txt

@@ -1,11 +1,35 @@
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.5)
 
 project(Blackhole)
 
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_BINARY_DIR})
+list(APPEND CMAKE_PREFIX_PATH ${CMAKE_BINARY_DIR})
+
+if(NOT EXISTS "${CMAKE_BINARY_DIR}/conan.cmake")
+  message(STATUS "Downloading conan.cmake from https://github.com/conan-io/cmake-conan")
+  file(DOWNLOAD "https://raw.githubusercontent.com/conan-io/cmake-conan/v0.16.1/conan.cmake"
+                "${CMAKE_BINARY_DIR}/conan.cmake"
+                EXPECTED_HASH SHA256=396e16d0f5eabdc6a14afddbcfff62a54a7ee75c6da23f32f7a31bc85db23484
+                TLS_VERIFY ON)
+endif()
+
+include(${CMAKE_BINARY_DIR}/conan.cmake)
+
+conan_cmake_configure(REQUIRES imgui/1.86 glfw/3.3.6 glew/2.2.0 glm/0.9.9.8 stb/cci.20210713
+                      GENERATORS cmake_find_package)
+
+conan_cmake_autodetect(settings)
+
+conan_cmake_install(PATH_OR_REFERENCE .
+                    BUILD missing
+                    REMOTE conancenter
+                    SETTINGS ${settings})
+
 find_package(imgui REQUIRED)
 find_package(glfw3 REQUIRED)
 find_package(GLEW REQUIRED)
 find_package(glm REQUIRED)
+find_package(stb REQUIRED)
 
 file(GLOB SRC_FILES
   "${PROJECT_SOURCE_DIR}/src/*.h"
@@ -19,9 +43,7 @@ target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE imgui::imgui)
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE glfw)
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE GLEW::GLEW)
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE glm::glm)
-
-find_path(STB_INCLUDE_DIRS "stb.h")
-target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE ${STB_INCLUDE_DIRS})
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE stb::stb)
 
 target_compile_features(${CMAKE_PROJECT_NAME} PRIVATE cxx_std_17)