Get codebase completely working with LLVM

You can now build Cosmopolitan with Clang:

    make -j8 MODE=llvm
    o/llvm/examples/hello.com

The assembler and linker code is now friendly to LLVM too.
So it's not needed to configure Clang to use binutils under
the hood. If you love LLVM then you can now use pure LLVM.

libc/tinymath/exp2.S

@@ -19,10 +19,10 @@
 #include "libc/macros.h"
 .source	__FILE__
 
-/	Returns 2^𝑥.
-/
-/	@param	𝑥 is a double passed in the lower quadword of %xmm0
-/	@return	result in lower quadword of %xmm0
+//	Returns 2^𝑥.
+//
+//	@param	𝑥 is a double passed in the lower quadword of %xmm0
+//	@return	result in lower quadword of %xmm0
 exp2:
 	ezlea	exp2l,ax
 	jmp	_d2ld2