From 81beca397535d50830162af7a107c8ab4f64c9d1 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <anonymous.maarten@gmail.com>
Date: Thu, 8 Jul 2021 17:59:59 +0200
Subject: [PATCH] cmake: mark WinMain as an undefined symbol, when building
 with mingw

---
 cmake/win/WinFunctions.cmake | 13 +++++++++++++
 skeleton/CMakeLists.txt      | 12 +++++++-----
 src/CMakeLists.txt           |  2 ++
 3 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/cmake/win/WinFunctions.cmake b/cmake/win/WinFunctions.cmake
index b7f0267..d693af3 100644
--- a/cmake/win/WinFunctions.cmake
+++ b/cmake/win/WinFunctions.cmake
@@ -4,4 +4,17 @@ set(GLFW3_STATIC_INIT ON)
 set(LIBRW_STATIC_RUNTIME_DEFAULT ON)
 
 function(librw_platform_target TARGET)
+    cmake_parse_arguments(LPT "PROVIDES_WINMAIN" "" "" ${ARGN})
+    get_target_property(TARGET_TYPE "${TARGET}" TYPE)
+
+    if(MINGW)
+        if(LPT_PROVIDES_WINMAIN AND TARGET_TYPE MATCHES "^(INTERFACE|SHARED|STATIC)_LIBRARY$")
+            # Start with the WinMain symbol marked as undefined.
+            # This will prevent the linker ignoring a WinMain symbol.
+            if(CMAKE_SIZEOF_VOID_P EQUAL 4)
+                target_link_options(${TARGET} INTERFACE -Wl,--undefined,_WinMain@16)
+            endif()
+            target_link_options(${TARGET} INTERFACE -Wl,--undefined,WinMain)
+        endif()
+    endif()
 endfunction()
diff --git a/skeleton/CMakeLists.txt b/skeleton/CMakeLists.txt
index 3083adc..276e9d7 100644
--- a/skeleton/CMakeLists.txt
+++ b/skeleton/CMakeLists.txt
@@ -31,17 +31,19 @@ set_target_properties(librw_skeleton
         EXPORT_NAME skeleton
 )
 
-target_link_libraries(librw_skeleton
-    PRIVATE
-        librw
-)
-
 target_include_directories(librw_skeleton
     PUBLIC
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
         $<INSTALL_INTERFACE:${LIBRW_INSTALL_INCLUDEDIR}/skeleton>
 )
 
+target_link_libraries(librw_skeleton
+    PRIVATE
+        librw
+)
+
+librw_platform_target(librw_skeleton PROVIDES_WINMAIN INSTALL)
+
 if(LIBRW_INSTALL)
     install(
         FILES
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5b16901..0521351 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -192,6 +192,8 @@ elseif(LIBRW_PLATFORM_D3D9)
     )
 endif()
 
+librw_platform_target(librw INSTALL)
+
 if(LIBRW_INSTALL)
     install(
         FILES