CI(build-tools): Remove libpq from build image (#8206)

## Problem
We use `build-tools` image as a base image to build other images, and it
has a pretty old `libpq-dev` installed (v13; it wasn't that old until I
removed system Postgres 14 from `build-tools` image in
https://github.com/neondatabase/neon/pull/6540)

## Summary of changes
- Remove `libpq-dev` from `build-tools` image
- Set `LD_LIBRARY_PATH` for tests (for different Postgres binaries that
we use, like psql and pgbench)
- Set `PQ_LIB_DIR` to build Storage Controller
- Set `LD_LIBRARY_PATH`/`DYLD_LIBRARY_PATH` in the Storage Controller
where it calls Postgres binaries

.github/workflows/benchmarking.yml

@@ -379,6 +379,10 @@ jobs:
 
     - name: Add Postgres binaries to PATH
       run: |
+        LD_LIBRARY_PATH="${POSTGRES_DISTRIB_DIR}/v${DEFAULT_PG_VERSION}/lib"
+        export LD_LIBRARY_PATH
+        echo "LD_LIBRARY_PATH=${LD_LIBRARY_PATH}" >> $GITHUB_ENV
+
         ${POSTGRES_DISTRIB_DIR}/v${DEFAULT_PG_VERSION}/bin/pgbench --version
         echo "${POSTGRES_DISTRIB_DIR}/v${DEFAULT_PG_VERSION}/bin" >> $GITHUB_PATH
 

.github/workflows/build-build-tools-image.yml

@@ -82,6 +82,7 @@ jobs:
           tags: neondatabase/build-tools:${{ inputs.image-tag }}-${{ matrix.arch }}
 
       - name: Remove custom docker config directory
+        if: always()
         run: |
           rm -rf /tmp/.docker-custom
 

.github/workflows/build_and_test.yml

@@ -335,6 +335,8 @@ jobs:
 
       - name: Run cargo build
         run: |
+          PQ_LIB_DIR=$(pwd)/pg_install/v16/lib
+          export PQ_LIB_DIR
           ${cov_prefix} mold -run cargo build $CARGO_FLAGS $CARGO_FEATURES --bins --tests
 
       # Do install *before* running rust tests because they might recompile the
@@ -383,6 +385,11 @@ jobs:
         env:
           NEXTEST_RETRIES: 3
         run: |
+          PQ_LIB_DIR=$(pwd)/pg_install/v16/lib
+          export PQ_LIB_DIR
+          LD_LIBRARY_PATH=$(pwd)/pg_install/v16/lib
+          export LD_LIBRARY_PATH
+
           #nextest does not yet support running doctests
           cargo test --doc $CARGO_FLAGS $CARGO_FEATURES
 

.github/workflows/neon_extra_builds.yml

@@ -232,12 +232,19 @@ jobs:
 
       - name: Run cargo build
         run: |
+          PQ_LIB_DIR=$(pwd)/pg_install/v16/lib
+          export PQ_LIB_DIR
           mold -run cargo build --locked $CARGO_FLAGS $CARGO_FEATURES --bins --tests -j$(nproc)
 
       - name: Run cargo test
         env:
           NEXTEST_RETRIES: 3
         run: |
+          PQ_LIB_DIR=$(pwd)/pg_install/v16/lib
+          export PQ_LIB_DIR
+          LD_LIBRARY_PATH=$(pwd)/pg_install/v16/lib
+          export LD_LIBRARY_PATH
+
           cargo nextest run $CARGO_FEATURES -j$(nproc)
 
           # Run separate tests for real S3