Build: stamp the real commit into the version string

Builds were reporting whichever commit cmake last configured against, not the
one being built. rpcs3/git-version.h is generated at CONFIGURE time, and
build-variants.sh deliberately skips reconfiguring an already-correct build
dir because re-running cmake regenerates LLVM's headers and costs a full
rebuild. So the stamp froze, and every build after that lied about itself.

The gap was wide. HEAD is 20120-da26a455; the header on disk still said
19985-91952ae4, a commit from before 0.9.2.

This is not cosmetic. A tester running 0.9.3 reported that older commit in
their log, which sent an investigation hunting for a regression among upstream
ISO changes their build did not contain, and very nearly had a fix built and
sent for a version they were not running. A build that misreports itself makes
every report from it ambiguous.

stamp-git-version.sh writes the header from HEAD and is called by both build
entry points before anything compiles. It only writes when the contents differ,
so an unchanged HEAD does not force a rebuild, and ninja rebuilds just the
translation units that include it.

android/build-play-aab.sh

@@ -88,6 +88,9 @@ NDK_DIR="$(ls -d "$ANDROID_HOME/ndk/"*/ 2>/dev/null | sort -V | tail -1)"
 STRIP="${NDK_DIR}toolchains/llvm/prebuilt/darwin-x86_64/bin/llvm-strip"
 [ -x "$STRIP" ] || { echo "FAIL: llvm-strip not found under $ANDROID_HOME/ndk" >&2; exit 1; }
 
+# Same reason as build-variants.sh: cmake only regenerates this at configure time.
+bash "$HERE/stamp-git-version.sh"
+
 echo "==> Staging the legacy core"
 mkdir -p "$JNI"
 "$STRIP" --strip-unneeded -o "$JNI/libarmsx3-core.so" "$CORE_SRC"

android/build-variants.sh

@@ -188,6 +188,10 @@ build_variant() {
 	echo "==> $name: $out"
 }
 
+# Stamp the version before anything builds, or every APK reports whichever commit cmake
+# last configured against rather than the one being built.
+bash "$ROOT/android/stamp-git-version.sh"
+
 for v in $VARIANTS; do
 	build_variant "$v"
 done

android/stamp-git-version.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+#
+# Refresh rpcs3/git-version.h from the current HEAD.
+#
+# cmake generates this header, but only when it CONFIGURES, and build-variants.sh deliberately
+# skips reconfiguring an already-correct build dir because re-running cmake regenerates LLVM's
+# generated headers and costs a full rebuild. So the version stamp froze at whenever cmake last
+# ran, and every build after that reported an old commit.
+#
+# That is not cosmetic. A tester on 0.9.3 reported a 0.9.1-era commit in their log, which sent
+# an investigation looking for a regression in commits their build did not contain. A build that
+# misreports itself makes every bug report ambiguous.
+#
+# Writing the header directly is enough: ninja sees it change and rebuilds only what includes it.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+OUT="$ROOT/rpcs3/git-version.h"
+
+cd "$ROOT"
+COUNT="$(git rev-list HEAD --count)"
+SHA="$(git rev-parse --short=8 HEAD)"
+BRANCH="$(git rev-parse --abbrev-ref HEAD)"
+
+NEW="// This is a generated file.
+
+#define RPCS3_GIT_VERSION \"${COUNT}-${SHA}\"
+#define RPCS3_GIT_BRANCH \"${BRANCH}\"
+#define RPCS3_GIT_FULL_BRANCH \"local_build\"
+
+// If you don't want this file to update/recompile, change to 1.
+#define RPCS3_GIT_VERSION_NO_UPDATE 0"
+
+# Only write when it differs, so an unchanged HEAD does not force a rebuild.
+if [ ! -f "$OUT" ] || [ "$(cat "$OUT")" != "$NEW" ]; then
+	printf '%s' "$NEW" > "$OUT"
+	echo "==> git-version.h: ${COUNT}-${SHA} (${BRANCH})"
+else
+	echo "==> git-version.h already current: ${COUNT}-${SHA}"
+fi