diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index 1df0a846e..c590ccf28 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -209,7 +209,7 @@ StringSet Settings::getDefaultExtraPlatforms()
     StringSet levels = computeLevels();
     for (auto iter = levels.begin(); iter != levels.end(); ++iter)
         extraPlatforms.insert(*iter + "-linux");
-#elif __APPLE__
+#elif defined(__APPLE__)
     // Rosetta 2 emulation layer can run x86_64 binaries on aarch64
     // machines. Note that we can’t force processes from executing
     // x86_64 in aarch64 environments or vice versa since they can
diff --git a/src/libstore/unix/user-lock.cc b/src/libstore/unix/user-lock.cc
index eb0bac887..2bee277f9 100644
--- a/src/libstore/unix/user-lock.cc
+++ b/src/libstore/unix/user-lock.cc
@@ -196,7 +196,7 @@ bool useBuildUsers()
     #ifdef __linux__
     static bool b = (settings.buildUsersGroup != "" || settings.autoAllocateUids) && isRootUser();
     return b;
-    #elif __APPLE__
+    #elif defined(__APPLE__)
     static bool b = settings.buildUsersGroup != "" && isRootUser();
     return b;
     #else
diff --git a/src/libutil/current-process.cc b/src/libutil/current-process.cc
index 8aef47146..926714ae8 100644
--- a/src/libutil/current-process.cc
+++ b/src/libutil/current-process.cc
@@ -108,7 +108,7 @@ std::optional<Path> getSelfExe()
     {
         #if defined(__linux__) || defined(__GNU__)
         return readLink("/proc/self/exe");
-        #elif __APPLE__
+        #elif defined(__APPLE__)
         char buf[1024];
         uint32_t size = sizeof(buf);
         if (_NSGetExecutablePath(buf, &size) == 0)