docs: changelog for macro expansion and the corrected corpus audit

Assisted-by: GLM 5.3 Flash

CHANGELOG.md

@@ -9,6 +9,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **Macro expansion and include splicing.**  `gasm asm`, `gasm diff` and
+  `gasm audit-instructions` now preprocess assembly the way the
+  toolchain does: object and parameterised `#define` macros expand at
+  the point of use, `#undef` and the `#ifdef`/`#ifndef`/`#else`/
+  `#endif` family select branches, `#include` splices headers resolved
+  through the source directory and the new repeatable `-I` flag, `;`
+  separates statements, and constant expressions left in operands
+  (`$(32-7)`, `$~63`, `(index*4)(base)`) fold at parse.  Expansion
+  happens only on the assembly path: `gasm lint`, `gasm fmt` and the
+  language server keep reading the raw file.
 - **The GOROOT instruction wave, part 1.**  The encoder now covers the
   instruction families GOROOT's real code uses that gasm lacked,
   byte-verified against `go tool asm`: on amd64 the carry ALU, the
@@ -129,6 +139,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **The corpus audit attempts fewer files that no build would compile.**
+  Files named for Go ports gasm does not target (arm, 386, s390x, ...)
+  are reported as other-port and never attempted, the headline rate is
+  computed over attemptable files, and the audit searches the
+  toolchain's shipped headers (funcdata.h and friends) automatically.
 - **riscv64 JALR silently jumped to the wrong register.**  The trampoline
   form `JALR X0, 0(X5)` read the memory operand's base as the destination,
   encoding a jump to X0 with no diagnostic; the destination is the first