fix(ci/edriver): add musl-obstack-dev for elfutils configure on Alpine

elfutils configure also checks AC_SEARCH_LIBS([_obstack_free], [obstack]).
On glibc this resolves to libc; on musl it requires a standalone package.
Alpine 3.20 has musl-obstack-dev (void-linux/musl-obstack, main repo).

Three musl compatibility packages now required for vendored elfutils:
  argp-standalone  -> -largp  (argp_parse)
  musl-fts-dev     -> -lfts   (fts_close)
  musl-obstack-dev -> -lobstack (_obstack_free)

Author: chriskaliX

.github/workflows/ci-edriver.yaml

@@ -72,7 +72,8 @@ jobs:
             pkgconf \
             autoconf automake libtool gettext-dev flex bison gawk perl \
             argp-standalone \
-            musl-fts-dev
+            musl-fts-dev \
+            musl-obstack-dev
 
       # ── Ubuntu (aarch64) ────────────────────────────────────────────────
       - name: Install build dependencies (Ubuntu / aarch64)