PG-2398 Enable support for PostgreSQL 16 in our CI

Most of the work doing this was related to making everything build
without injection points as injection points were first added in
PostgreSQL 17.

Author: jeltz

.github/workflows/matrix.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        pg_version: [17, 18]
+        pg_version: [16, 17, 18]
         os: [ubuntu-24.04]
         compiler: [gcc, clang]
         build_type: [debugoptimized]
@@ -51,7 +51,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        pg_version: [17, 18]
+        pg_version: [16, 17, 18]
         os: [ubuntu-24.04-arm]
         compiler: [gcc, clang]
         build_type: [debugoptimized]

ci_scripts/build-and-install-psp.sh

@@ -7,26 +7,29 @@ ARGS=
 SCRIPT_DIR="$(cd -- "$(dirname "$0")" >/dev/null 2>&1; pwd -P)"
 INSTALL_DIR="$SCRIPT_DIR/../../pginst"
 PSP_DIR="$SCRIPT_DIR/../../postgres"
+PG_CONFIG="$INSTALL_DIR/bin/pg_config"
+
+PG_VERSION=$("$PG_CONFIG" --version | sed -n 's/PostgreSQL \([0-9]*\).*/\1/p')
 
 INSTALL_INJECTION_POINTS=0
 
 case "$1" in
     debug)
         echo "Building with debug option"
-        ARGS+=" --enable-cassert --enable-injection-points"
+        ARGS+=" --enable-cassert"
         INSTALL_INJECTION_POINTS=1
         ;;
 
     debugoptimized)
         echo "Building with debugoptimized option"
         export CFLAGS="-O2"
-        ARGS+=" --enable-cassert --enable-injection-points"
+        ARGS+=" --enable-cassert"
         INSTALL_INJECTION_POINTS=1
         ;;
 
     coverage)
         echo "Building with coverage option"
-        ARGS+=" --enable-injection-points --enable-coverage"
+        ARGS+=" --enable-coverage"
         INSTALL_INJECTION_POINTS=1
         ;;
 
@@ -42,8 +45,18 @@ case "$1" in
         ;;
 esac
 
+if [ "$PG_VERSION" -lt 17 ]; then
+    INSTALL_INJECTION_POINTS=0
+fi
+
+if [ "$INSTALL_INJECTION_POINTS" = 1 ]; then
+     ARGS+=" --enable-injection-points"
+fi
+
 if [[ "$OSTYPE" == "linux-gnu"* ]]; then
-    ARGS+=" --with-liburing"
+    if [ "$PG_VERSION" -ge 17 ]; then
+        ARGS+=" --with-liburing"
+    fi
     NCPU=$(nproc)
 elif [[ "$OSTYPE" == "darwin"* ]]; then
     NCPU=$(sysctl -n hw.ncpu)