Tidy up some extensions and remove some ifdefs

Since this codebase is already extremely nonportable, I've decided to
relax the obsessive ifdef-else-error usage around all the extensions.
From now on, if there's no alternative to using an extension, we can
just use that extension. If it's possible to do something in a
relatively portable way, we can still try to do that in order to make
the code somewhat reusable, in contexts where that makes sense.

I also decided to use langext.h for naked functions and tail calls. If
that's used in another codebase build with a different compiler, those
just won't work, but that's fine. The benefit is really just that
there's less ceremony in places where those are used, because it's
likely there'll be a few more such places in the future, and it gets
annoying reading all the double-underscore stuff all over the place.

I still kind of want to do something about all the _WIN32 ifdefs too,
but I've realised that doing so will lead to almost nothing actually
being built on Linux. Then again, none of it currently runs on Linux so
I guess that's a moot point. Will worry about it later, anyway.

1 files changed, 1 insertions, 8 deletions

diff --git a/src/l4d1democompat.c b/src/l4d1democompat.c
index 4b84dd3..eff6ad0 100644
--- a/src/l4d1democompat.c
+++ b/src/l4d1democompat.c
@@ -114,14 +114,7 @@ static void VCALLCONV hook_ReadDemoHeader(struct CDemoFile *this) {
 	orig_ReadDemoHeader(this);
 }
 
-#if defined(__clang__)
-__attribute((naked))
-#elif defined(_MSC_VER)
-#error Inadequate inline assembly syntax, use Clang instead.
-#else
-#error No way to do naked functions! We only support Clang at the moment.
-#endif
-static int hook_midpoint() {
+static asm_only int hook_midpoint() {
 	__asm volatile (
 		"push eax\n"
 		"mov eax, %1\n"