--- a/SConstruct
+++ b/SConstruct
@@ -150,10 +150,6 @@
     'packaging/rpm/gpsd.spec',
     'packet_names.h',
     'Qgpsmm.pc',
-    'ubxtool',
-    'xgps',
-    'xgpsspeed',
-    'zerk',
    ]
 
 generated_www = [
@@ -172,10 +168,6 @@
     "gpscat",
     "gpsfake",
     "gpsprof",
-    "ubxtool",
-    "xgps",
-    "xgpsspeed",
-    "zerk",
 ]
 
 # All man pages.  Always build them all.
@@ -205,10 +197,6 @@
     "man/ntpshmmon.1": "man/ntpshmmon.xml",
     "man/ppscheck.8": "man/ppscheck.xml",
     "man/srec.5": "man/srec.xml",
-    "man/ubxtool.1": "man/ubxtool.xml",
-    "man/xgps.1": "man/gps.xml",
-    "man/xgpsspeed.1": "man/gps.xml",
-    "man/zerk.1": "man/zerk.xml",
 }
 
 # doc files to install in share/gpsd/doc
@@ -1964,6 +1952,28 @@
         "valgrind-audit.py"
     ]
 
+    if env['greis']:
+        generated_sources.extend(["zerk"])
+        python_progs.extend(["zerk"])
+        all_manpages.update({
+            "man/zerk.1": "man/zerk.xml",
+        })
+
+    if env['ublox']:
+        generated_sources.extend(["ubxtool"])
+        python_progs.extend(["ubxtool"])
+        all_manpages.update({
+            "man/ubxtool.1": "man/ubxtool.xml",
+        })
+
+    if env['xgps']:
+        generated_sources.extend(["xgps", "xgpsspeed"])
+        python_progs.extend(["xgps", "xgpsspeed"])
+        all_manpages.update({
+            "man/xgps.1": "man/xgps.xml",
+            "man/xgpsspeed.1": "man/xgps.xml",
+        })
+
     # Dependencies for imports in test programs
     env.Depends('tests/test_clienthelpers.py',
                 ['gps/__init__.py', 'gps/clienthelpers.py', 'gps/misc.py'])