From 34f1be968f731dd6c8cb1f515415d58acba8b532 Mon Sep 17 00:00:00 2001
From: Jean Boussier <jean.boussier@gmail.com>
Date: Tue, 30 Jan 2024 17:43:36 +0100
Subject: [PATCH] Fix extconf.rb to look for fdatasync in unistd.h

Fix: https://github.com/Shopify/bootsnap/issues/470
---
 CHANGELOG.md            | 2 ++
 ext/bootsnap/bootsnap.c | 1 +
 ext/bootsnap/extconf.rb | 2 +-
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb9d2f6..6c40bc0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 # Unreleased
 
+* Fix a potential compilation issue on some systems. See #470.
+
 # 1.18.1
 
 * Handle `EPERM` errors when opening files with `O_NOATIME`.
diff --git a/ext/bootsnap/bootsnap.c b/ext/bootsnap/bootsnap.c
index 326aade..72c5b06 100644
--- a/ext/bootsnap/bootsnap.c
+++ b/ext/bootsnap/bootsnap.c
@@ -18,6 +18,7 @@
 #include <sys/types.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <unistd.h>
 #include <sys/stat.h>
 
 #ifndef O_NOATIME
diff --git a/ext/bootsnap/extconf.rb b/ext/bootsnap/extconf.rb
index 5d61d38..e7c1160 100644
--- a/ext/bootsnap/extconf.rb
+++ b/ext/bootsnap/extconf.rb
@@ -3,7 +3,7 @@
 require "mkmf"
 
 if %w[ruby truffleruby].include?(RUBY_ENGINE)
-  have_func "fdatasync", "fcntl.h"
+  have_func "fdatasync", "unistd.h"
 
   unless RUBY_PLATFORM.match?(/mswin|mingw|cygwin/)
     append_cppflags ["_GNU_SOURCE"] # Needed of O_NOATIME