libva-v4l2-request-fourier: -Db_lto=false (closes #17)

CI binary segfaulted on HEVC vaEndPicture even though
/etc/makepkg.conf has OPTIONS=(... !lto ...). Root cause: arch-meson's
wrapper hard-codes `-D b_lto=true` regardless of makepkg.conf, so
the binary still gets cross-function ICF (Identical Code Folding)
under -O2 + LTO.

HEVC is the only codec in the campaign that submits a per-frame chain
of 4 control structs (SPS + PPS + DECODE_PARAMS + SLICE_PARAMS); ICF
finds a near-duplicate per-codec helper across the codec dispatch and
merges them, then the wrong instance's local stack layout is invoked
on the HEVC path → SEGV. The other 4 codecs (H.264, VP8, VP9, MPEG-2)
submit fewer/simpler control structs and tolerate the folding by
accident.

Empirical confirmation from the issue body's binary bisection:

  meson build (default debugoptimized)     485 KB   HEVC ✓
  arch-meson + --buildtype=release          145 KB   HEVC ✓
  arch-meson + release + -flto              76 KB   HEVC SEGV
  CI build (this package, 7ac934e-1)        133 KB   HEVC SEGV

Fix: append `-Db_lto=false` to the arch-meson invocation.
pkgrel 1 -> 2.

arch/libva-v4l2-request-fourier/PKGBUILD

@@ -36,7 +36,7 @@ _commit=7ac934e0c5420814c7a5fc3e2a2f08251d590d9e
 # build time by pkgver() below; the static value here is a placeholder
 # so AUR-style consumers see something coherent before src/ exists.
 pkgver=1.0.0.r348.7ac934e
-pkgrel=1
+pkgrel=2
 pkgdesc="VA-API backend for V4L2 stateless decoders (multiplanar fork — fourier umbrella)"
 arch=('aarch64')
 url="https://git.reauktion.de/marfrit/libva-v4l2-request-fourier"
@@ -61,7 +61,15 @@ build() {
     cd "${srcdir}/${_upstreampkg}-fourier"
     # meson_options.txt only exposes 'kernel_headers' — leave it empty to
     # use system /usr/include kernel UAPI headers. No per-codec toggles.
-    arch-meson build --buildtype=release
+    #
+    # b_lto=false: override arch-meson's wrapper default of `-D b_lto=true`,
+    # which the makepkg.conf OPTIONS=(..., !lto, ...) line does NOT actually
+    # override (arch-meson hard-codes b_lto=true). The hand-built reproducer
+    # from issue #17 shows: LTO/ICF kernel-folds per-codec helpers and HEVC's
+    # multi-control-struct chain (SPS+PPS+DECODE_PARAMS+SLICE_PARAMS) gets a
+    # wrong helper-instance pulled in at vaEndPicture → segfault. The 4 other
+    # codecs (single-control-struct) tolerate the folding by accident.
+    arch-meson build --buildtype=release -Db_lto=false
     meson compile -C build
 }