diff --git a/libs/panners/1in2out/wscript b/libs/panners/1in2out/wscript
index 70c34d0779..c26cc0546d 100644
--- a/libs/panners/1in2out/wscript
+++ b/libs/panners/1in2out/wscript
@@ -22,7 +22,9 @@ def build(bld):
     obj = bld(features = 'cxx cxxshlib')
     obj.source = [ 'panner_1in2out.cc' ]
     obj.export_includes = ['.']
-    obj.cxxflags     = '-DPACKAGE="libardour_pan1in2out"'
+    obj.defines     = [ 'PACKAGE="libardour_pan1in2out"' ]
+    if bld.is_defined ('INTERNAL_SHARED_LIBS'):
+        obj.defines += [ 'LIBARDOUR_DLL=1', 'LIBPBD_DLL=1' ]
     obj.includes     = ['.']
     obj.name         = 'libardour_pan1in2out'
     obj.target       = 'pan1in2out'
diff --git a/libs/panners/2in2out/wscript b/libs/panners/2in2out/wscript
index 8288ef28f7..72eeda917f 100644
--- a/libs/panners/2in2out/wscript
+++ b/libs/panners/2in2out/wscript
@@ -22,7 +22,9 @@ def build(bld):
     obj = bld(features = 'cxx cxxshlib')
     obj.source = [ 'panner_2in2out.cc' ]
     obj.export_includes = ['.']
-    obj.cxxflags     = '-DPACKAGE="libardour_pan2in2out"'
+    obj.defines     = [ 'PACKAGE="libardour_pan2in2out"' ]
+    if bld.is_defined ('INTERNAL_SHARED_LIBS'):
+        obj.defines += [ 'LIBARDOUR_DLL=1', 'LIBPBD_DLL=1' ]
     obj.includes     = ['.']
     obj.name         = 'libardour_pan2in2out'
     obj.target       = 'pan2in2out'
diff --git a/libs/panners/vbap/wscript b/libs/panners/vbap/wscript
index c6ba94261f..8d4356b828 100644
--- a/libs/panners/vbap/wscript
+++ b/libs/panners/vbap/wscript
@@ -22,7 +22,9 @@ def build(bld):
     obj = bld(features = 'cxx cxxshlib')
     obj.source = [ 'vbap_speakers.cc', 'vbap.cc'  ]
     obj.export_includes = ['.']
-    obj.cxxflags     = '-DPACKAGE="libardour_panvbap"'
+    obj.defines     = [ 'PACKAGE="libardour_panvbap"' ]
+    if bld.is_defined ('INTERNAL_SHARED_LIBS'):
+        obj.defines += [ 'LIBARDOUR_DLL=1', 'LIBCONTROLCP_DLL_=1', 'LIBPBD_DLL=1' ]
     obj.includes     = ['.']
     obj.name         = 'libardour_panvbap'
     obj.target       = 'panvbap'