Add support for including SDL3 headers in older toolchains

[madebr]

With these patches, I can successfully use the SDL3 headers with MSVC 6 (from 1998).

Description

Existing Issue(s)

[icculus]

Let's have the headers automatically define SDL_NOLONGLONG if _MSC_VER <= whatever Visual C++ 6.0 sets it to.

@sezero, I assume Watcom has "long long", right?

[sezero]

@sezero, I assume Watcom has "long long", right?

Versions of it that matter (e.g. >= 1.9, maybe even older) do.

[sezero]

@sezero, I assume Watcom has "long long", right?

Versions of it that matter (e.g. >= 1.9, maybe even older) do.

E.g.: The Makefile.w32 in sdl2-compat has been working since
the beginning using ow1.9

[madebr]

About the introduction of __debugbreak and _BitScanReverse, I asked ChatGPT about this.
I hope it was not hallucinating..

I also don't know what MSVC version introduced long long, ChatGPT thinks it was 2010 so SDL_NOLONGLONG should be defined for _MSC_VER < 1600

[sezero]

I also don't know what MSVC version introduced long long,

vs2005, at least, has it, if I recall correctly

[icculus]

Random webpage I found said VS2013, but that seems way too late.

So now I'm bisecting it. :)

[icculus]

Visual Studio.NET 2003 is the first to support it. _MSC_VER == 1310 (decimal, not hex).

[madebr]

While you maybe still have the old toolchaibs set up, are the minimum versions I used for _BitScanReverse and __debugbreak correct?
Should we have an asm { int 3 } implementation for older x86 msvc?

[sezero]

About the introduction of __debugbreak

Maybe add the following for old MSVC versions? (not tested)

--- SDL_assert.h~
+++ SDL_assert.h
@@ -131,6 +131,8 @@
     /* Don't include intrin.h here because it contains C++ code */
     extern void __cdecl __debugbreak(void);
     #define SDL_TriggerBreakpoint() __debugbreak()
+#elif defined(_MSC_VER) && defined(_M_IX86)
+    #define SDL_TriggerBreakpoint() { _asm { int 0x03 } }
 #elif defined(ANDROID)
     #include <assert.h>
     #define SDL_TriggerBreakpoint() assert(0)

[icculus]

Go ahead and commit it, if someone actually reports it failing on Visual C++ 6.0, we'll fix it as the highest priority. :)

[sezero]

Go ahead and commit it,

Done as 61f13b9

if someone actually reports it failing on Visual C++ 6.0, we'll fix it as the highest priority. :)

Yes, with very most highest priority :))

[madebr]

On unknown platforms, SDL_TriggerBreakpoint currently becomes a no-op.

SDL/include/SDL3/SDL_assert.h

Lines 156 to 159 in 82125ec

	#else
	/* How do we trigger breakpoints on this platform? */
	#define SDL_TriggerBreakpoint()
	#endif

I think this might surprise people.
Would it be bad if SDL leaves SDL_TriggerBreakpoint undefined and trigger a compiler error?
This also allows users to define SDL_TriggerBreakpoint themselves.

[slouken]

On unknown platforms, SDL_TriggerBreakpoint currently becomes a no-op.

SDL/include/SDL3/SDL_assert.h

Lines 156 to 159 in 82125ec

	#else
	/* How do we trigger breakpoints on this platform? */
	#define SDL_TriggerBreakpoint()
	#endif

I think this might surprise people. Would it be bad if SDL leaves SDL_TriggerBreakpoint undefined and trigger a compiler error? This also allows users to define SDL_TriggerBreakpoint themselves.

Good point, let's remove that.