Add Dear ImPlot Library

Externals/implot/CMakeLists.txt

@@ -0,0 +1,23 @@
+if(NOT MSVC)
+  set(CMAKE_CXX_STANDARD 20)
+  set(CMAKE_CXX_STANDARD_REQUIRED ON)
+  set(CMAKE_CXX_EXTENSIONS OFF)
+endif()
+
+set(SRCS
+  implot/implot.cpp
+  implot/implot_items.cpp
+  implot/implot_demo.cpp
+)
+
+add_library(implot STATIC ${SRCS})
+dolphin_disable_warnings_msvc(implot)
+target_include_directories(implot
+  PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/implot"
+  PRIVATE imgui
+)
+
+target_link_libraries(implot
+  PRIVATE imgui
+  PRIVATE fmt::fmt
+)