Add 'make postgres' Makefile target.

That would build postgres and install it into REPO_ROOT/tmp_install where pageserver
integration tests would be able to find it.

.gitignore

@@ -1 +1,2 @@
 /target
+/tmp_install

Makefile

@@ -0,0 +1,34 @@
+#
+#   Purpose of this Makefile is to build and install postgres in a local directory
+# so that zenith intergation tests would find pg binaries and support files.
+#
+# 'make postgres' would do following:
+#
+#   1) run out-of-source build of postgres in REPO_ROOT/tmp_install/build directory (I'm reusing
+#  tmp_install path here since it is already present in .gitignore)
+#
+#   2) installs postgres to REPO_ROOT/tmp_install/
+#
+#   This Makefile is integrated with cargo build by the means of build.rs file (special file
+# that cargo build would run if it is present) which will call `make postgres` if there is no
+# tmp_install/bin/postgres binary.
+#
+
+../tmp_install/build/Makefile:
+	mkdir -p ../tmp_install/build && \
+		cd ../tmp_install/build && \
+		../../configure CFLAGS='-O0' --enable-debug --enable-cassert \
+			--enable-depend --with-libxml --prefix=/
+
+pg-configure: ../tmp_install/build/Makefile
+
+# this makefile would set env variables that would interfere with postgres build
+# preventing it from finding autogenerated headers. Hence 'env -i'
+pg-build: pg-configure
+	env -i make -j8 -C ../tmp_install/build
+
+postgres: pg-build
+	mkdir -p ../tmp_install/log
+	env -i make -C ../tmp_install/build \
+		DESTDIR=/Users/stas/code/postgres/tmp_install install \
+		> /Users/stas/code/postgres/tmp_install/log/install.log 2>&1

build.rs

@@ -0,0 +1,41 @@
+//
+//   Triggers postgres build if there is no postgres binary present at
+// 'REPO_ROOT/tmp_install/bin/postgres'.
+//
+//   I can see a lot of disadvantages with such automatization and main
+// advantage here is ability to build everything and run integration tests
+// in a bare repo by running 'cargo test'.
+//
+//   We can interceipt whether it is debug or release build and run
+// corresponding pg build. But it seems like an overkill for now.
+//
+// Problem #1 -- language server in my editor likes calling 'cargo build'
+// by himself. So if I delete tmp_install directory it would magically reappear
+// after some time. During this compilation 'cargo build' may whine about
+// "waiting for file lock on build directory".
+//
+// Problem #2 -- cargo build would run this only if something is changed in
+// the crate.
+//
+//   And generally speaking postgres is not a build dependency for the pageserver,
+// just for integration tests. So let's not mix that. I'll leave this file in
+// place for some time just in case if anybody would start doing the same.
+//
+
+// use std::path::Path;
+// use std::process::{Command};
+
+fn main() {
+    // // build some postgres if it is not done none yet
+    // if !Path::new("../tmp_install/bin/postgres").exists() {
+    //     let make_res = Command::new("make")
+    //         .arg("postgres")
+    //         .env_clear()
+    //         .status()
+    //         .expect("failed to execute 'make postgres'");
+
+    //     if !make_res.success() {
+    //         panic!("postgres build failed");
+    //     }
+    // }
+}

src/control_plane.rs

@@ -45,10 +45,10 @@ impl ComputeControlPlane {
     pub fn local() -> ComputeControlPlane {
         // postgres configure and `make temp-install` are using this path
         let pg_install_dir = Path::new(env!("CARGO_MANIFEST_DIR"))
-            .join("../build/tmp_install/usr/local/pgsql");
+            .join("../tmp_install/");
 
         let work_dir = Path::new(env!("CARGO_MANIFEST_DIR"))
-            .join("../tmp_check/zenith");
+            .join("tmp_install/");
 
         ComputeControlPlane {
             pg_install_dir: pg_install_dir,
@@ -190,7 +190,6 @@ impl PostgresNode {
 }
 
 impl Drop for PostgresNode {
-
     // destructor to clean up state after test is done
     // TODO: leave everything in place if test is failed
     // TODO: put logs to a separate location to run `tail -F` on them