inline ctags alpine script (#803)

Remove the dependency on the sourcegraph monorepo

install-ctags-alpine.sh

@@ -1,7 +1,45 @@
 #!/bin/sh
+
+# This script installs universal-ctags within an alpine container.
+
+# Commit hash of github.com/universal-ctags/ctags.
+# Last bumped 2023-10-24.
+CTAGS_VERSION=v6.0.0
+CTAGS_ARCHIVE_TOP_LEVEL_DIR=ctags-6.0.0
+# When using commits you can rely on
+# CTAGS_ARCHIVE_TOP_LEVEL_DIR=ctags-$CTAGS_VERSION
+
+cleanup() {
+  apk --no-cache --purge del ctags-build-deps || true
+  cd /
+  rm -rf /tmp/ctags-$CTAGS_VERSION
+}
+
+trap cleanup EXIT
+
 set -eux
-# shellcheck disable=SC3040
-set -o pipefail || true
-# Commit from 2023-10-24. Please always pick a commit from the main branch.
-export SOURCEGRAPH_COMMIT=45a6748bb491513b9e1162d888711ca9b3bb4303
-wget -O - https://raw.githubusercontent.com/sourcegraph/sourcegraph/$SOURCEGRAPH_COMMIT/cmd/symbols/ctags-install-alpine.sh | sh
+
+apk --no-cache add \
+  --virtual ctags-build-deps \
+  autoconf \
+  automake \
+  binutils \
+  curl \
+  g++ \
+  gcc \
+  jansson-dev \
+  make \
+  pkgconfig
+
+# ctags is dynamically linked against jansson
+apk --no-cache add jansson
+
+NUMCPUS=$(grep -c '^processor' /proc/cpuinfo)
+
+# Installation
+curl --retry 5 "https://codeload.github.com/universal-ctags/ctags/tar.gz/$CTAGS_VERSION" | tar xz -C /tmp
+cd /tmp/$CTAGS_ARCHIVE_TOP_LEVEL_DIR
+./autogen.sh
+./configure --program-prefix=universal- --enable-json
+make -j"$NUMCPUS" --load-average="$NUMCPUS"
+make install