diff --git a/gtk2_ardour/about.cc b/gtk2_ardour/about.cc
index ed6ca3e468..2007f06749 100644
--- a/gtk2_ardour/about.cc
+++ b/gtk2_ardour/about.cc
@@ -24,7 +24,6 @@
  */
 
 #include <algorithm>
-#include <unistd.h>
 #include <sys/types.h>
 #include <cstdio>
 #include <ctime>
diff --git a/gtk2_ardour/ardour_http.cc b/gtk2_ardour/ardour_http.cc
index fac214c112..81b80112cd 100644
--- a/gtk2_ardour/ardour_http.cc
+++ b/gtk2_ardour/ardour_http.cc
@@ -21,7 +21,6 @@
 
 #include <assert.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <cstring>
 
 #include <glibmm.h>
diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index 16d1b99638..9abf876a20 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -49,7 +49,6 @@
 
 #include <stdint.h>
 #include <fcntl.h>
-#include <unistd.h>
 #include <time.h>
 
 #include <glib.h>
diff --git a/gtk2_ardour/ardour_ui2.cc b/gtk2_ardour/ardour_ui2.cc
index d5b5797781..ca9286d1d0 100644
--- a/gtk2_ardour/ardour_ui2.cc
+++ b/gtk2_ardour/ardour_ui2.cc
@@ -32,7 +32,6 @@
 
 #include <fcntl.h>
 #include <signal.h>
-#include <unistd.h>
 #include <cerrno>
 #include <iostream>
 #include <cmath>
diff --git a/gtk2_ardour/bundle_env_cocoa.cc b/gtk2_ardour/bundle_env_cocoa.cc
index 9e653139cf..1c50c05d71 100644
--- a/gtk2_ardour/bundle_env_cocoa.cc
+++ b/gtk2_ardour/bundle_env_cocoa.cc
@@ -17,8 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include <unistd.h>
-
 #include <string>
 #include <vector>
 #include <cerrno>
diff --git a/gtk2_ardour/curvetest.cc b/gtk2_ardour/curvetest.cc
index 3d0c149f4b..0f26821249 100644
--- a/gtk2_ardour/curvetest.cc
+++ b/gtk2_ardour/curvetest.cc
@@ -20,7 +20,6 @@
 #include <iostream>
 #include <fstream>
 #include <cfloat>
-#include <unistd.h>
 
 #include "ardour/automation_list.h"
 #include "evoral/Curve.h"
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index 07df306333..062ebdb708 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -32,7 +32,6 @@
 /* Note: public Editor methods are documented in public_editor.h */
 
 #include <stdint.h>
-#include <unistd.h>
 #include <cstdlib>
 #include <cmath>
 #include <string>
diff --git a/gtk2_ardour/editor_audio_import.cc b/gtk2_ardour/editor_audio_import.cc
index 13fb96c347..c11172c92a 100644
--- a/gtk2_ardour/editor_audio_import.cc
+++ b/gtk2_ardour/editor_audio_import.cc
@@ -25,9 +25,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <sys/time.h>
 #include <errno.h>
-#include <unistd.h>
 #include <algorithm>
 
 #include <sndfile.h>
diff --git a/gtk2_ardour/editor_export_audio.cc b/gtk2_ardour/editor_export_audio.cc
index a95d852d64..7f07cd2333 100644
--- a/gtk2_ardour/editor_export_audio.cc
+++ b/gtk2_ardour/editor_export_audio.cc
@@ -26,7 +26,6 @@
 /* Note: public Editor methods are documented in public_editor.h */
 
 #include <inttypes.h>
-#include <unistd.h>
 #include <climits>
 
 #include <ytkmm/messagedialog.h>
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 6f2f8e58b8..8d66ca0299 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -30,8 +30,6 @@
 
 /* Note: public Editor methods are documented in public_editor.h */
 
-#include <unistd.h>
-
 #include <cstdlib>
 #include <cmath>
 #include <string>
diff --git a/gtk2_ardour/editor_pt_import.cc b/gtk2_ardour/editor_pt_import.cc
index c6f0782fcb..d831dc0206 100644
--- a/gtk2_ardour/editor_pt_import.cc
+++ b/gtk2_ardour/editor_pt_import.cc
@@ -20,9 +20,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <sys/time.h>
 #include <errno.h>
-#include <unistd.h>
 #include <algorithm>
 
 #include "pbd/pthread_utils.h"
diff --git a/gtk2_ardour/linux_vst_gui_support.cc b/gtk2_ardour/linux_vst_gui_support.cc
index 0aded09abd..8e2c491d41 100644
--- a/gtk2_ardour/linux_vst_gui_support.cc
+++ b/gtk2_ardour/linux_vst_gui_support.cc
@@ -40,8 +40,6 @@
 #include <dlfcn.h>
 #include <string.h>
 #include <time.h>
-#include <unistd.h>
-#include <sys/time.h>
 
 struct ERect{
     short top;
diff --git a/gtk2_ardour/nsm.cc b/gtk2_ardour/nsm.cc
index 30e64455b8..ee0938d4e2 100644
--- a/gtk2_ardour/nsm.cc
+++ b/gtk2_ardour/nsm.cc
@@ -18,7 +18,6 @@
 /*******************************************************************************/
 
 #include <stdio.h>
-#include <unistd.h>
 
 #include "gtkmm2ext/application.h"
 
diff --git a/gtk2_ardour/nsmclient.cc b/gtk2_ardour/nsmclient.cc
index e440d33c6f..4bcd7b43ad 100644
--- a/gtk2_ardour/nsmclient.cc
+++ b/gtk2_ardour/nsmclient.cc
@@ -20,9 +20,12 @@
 #include "nsmclient.h"
 #include <string.h>
 #include <sys/types.h>
-#include <unistd.h>
 #include <stdlib.h>
 
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
 #ifndef COMPILER_MSVC
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #else
diff --git a/gtk2_ardour/sfdb_ui.cc b/gtk2_ardour/sfdb_ui.cc
index 768ddfba1b..5692472a14 100644
--- a/gtk2_ardour/sfdb_ui.cc
+++ b/gtk2_ardour/sfdb_ui.cc
@@ -38,7 +38,6 @@
 #include <cerrno>
 #include <sstream>
 
-#include <unistd.h>
 #include <limits.h>
 
 #include <glib.h>
diff --git a/gtk2_ardour/transcode_video_dialog.cc b/gtk2_ardour/transcode_video_dialog.cc
index b78ae8096e..4659a02da9 100644
--- a/gtk2_ardour/transcode_video_dialog.cc
+++ b/gtk2_ardour/transcode_video_dialog.cc
@@ -25,7 +25,6 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <unistd.h>
 
 #include <sigc++/bind.h>