diff --git a/docs/build.rst b/docs/build.rst
index 63b33d2e3..fb64b448f 100644
--- a/docs/build.rst
+++ b/docs/build.rst
@@ -90,6 +90,7 @@ Run-time dependencies:
 * ``freetype`` (not needed on macOS)
 * ``fontconfig`` (not needed on macOS)
 * ``libcanberra`` (not needed on macOS)
+* ``libsystemd`` (optional, not needed on non systemd systems)
 * ``ImageMagick`` (optional, needed to display uncommon image formats in the terminal)
 
 
diff --git a/kitty/systemd.c b/kitty/systemd.c
index 5d547a2ac..1c75929e0 100644
--- a/kitty/systemd.c
+++ b/kitty/systemd.c
@@ -5,7 +5,6 @@
  * Distributed under terms of the GPL3 license.
  */
 
-#define _GNU_SOURCE
 #include "data-types.h"
 #include "cleanup.h"
 
diff --git a/setup.py b/setup.py
index 886a1733d..c04d82055 100755
--- a/setup.py
+++ b/setup.py
@@ -633,8 +633,9 @@ def kitty_env(args: Options) -> Env:
         platform_libs = []
         with suppress(SystemExit, subprocess.CalledProcessError):
             cflags.extend(pkg_config('libsystemd', '--cflags-only-I', fatal=False))
-            has_systemd = 1
-            platform_libs.extend(pkg_config('libsystemd', '--libs'))
+            systemd_libs = pkg_config('libsystemd', '--libs')
+            platform_libs.extend(systemd_libs)
+            has_systemd = bool(systemd_libs)
     cppflags.append(f'-DKITTY_HAS_SYSTEMD={has_systemd}')
     cflags.extend(pkg_config('harfbuzz', '--cflags-only-I'))
     platform_libs.extend(pkg_config('harfbuzz', '--libs'))