- set Visual C++ compiler to use /permissive- mode and fixed the one error this generated.

This also means that Visual Studio 2015 is no longer supported as it has no proper standard conforming compile mode.

.appveyor.yml

@@ -8,7 +8,6 @@ clone_depth: 10
 
 image:
   - Visual Studio 2019
-  - Visual Studio 2015
 
 environment:
   matrix:

CMakeLists.txt

@@ -182,9 +182,9 @@ if( MSVC )
 	# Function-level linking
 	# Disable run-time type information
 	if ( HAVE_VULKAN )
-		set( ALL_C_FLAGS "/GF /Gy /GR- /DHAVE_VULKAN" )
+		set( ALL_C_FLAGS "/GF /Gy /GR- /permissive- /DHAVE_VULKAN" )
 	else()
-		set( ALL_C_FLAGS "/GF /Gy /GR-" )
+		set( ALL_C_FLAGS "/GF /Gy /GR- /permissive-" )
 	endif()
 
 	# Use SSE 2 as minimum always as the true color drawers needs it for __vectorcall

src/win32/i_crash.cpp

@@ -511,7 +511,7 @@ HANDLE WriteLogFile(HWND edit)
 //
 //==========================================================================
 
-void CreateCrashLog (char *custominfo, DWORD customsize, HWND richlog)
+void CreateCrashLog (const char *custominfo, DWORD customsize, HWND richlog)
 {
 	// Do not collect information more than once.
 	if (NumFiles != 0)

src/win32/i_main.cpp

@@ -98,7 +98,7 @@
 // EXTERNAL FUNCTION PROTOTYPES --------------------------------------------
 
 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
-void CreateCrashLog (char *custominfo, DWORD customsize, HWND richedit);
+void CreateCrashLog (const char *custominfo, DWORD customsize, HWND richedit);
 void DisplayCrashLog ();
 extern uint8_t *ST_Util_BitsForBitmap (BITMAPINFO *bitmap_info);
 void I_FlushBufferedConsoleStuff();