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, 4 insertions, 0 deletions

diff --git a/src/wincrt.c b/src/wincrt.c
index 9e8b9f5..9a0326b 100644
--- a/src/wincrt.c
+++ b/src/wincrt.c
@@ -10,6 +10,10 @@
 //
 // Is it actually reasonable to have to do any of this? Of course not.
 
+// Note: these functions have ifdefs with non-asm fallbacks just in case this
+// file is ever useful somewhere else, but generally we assume this codebase
+// will be built with Clang.
+
 int memcmp(const void *restrict x, const void *restrict y, unsigned int sz) {
 #if defined(__GNUC__) || defined(__clang__)
 	int a, b;