Engage thread-safe fftw planner in libardour

This way initialization happens constently, and independent from the GUI,
for session-utils, lua, headless..

libs/ardour/globals.cc

@@ -53,6 +53,10 @@
 #include <windows.h> // for LARGE_INTEGER
 #endif
 
+#ifdef HAVE_FFTW35F
+#include <fftw3.h>
+#endif
+
 #ifdef WINDOWS_VST_SUPPORT
 #include <fst.h>
 #endif
@@ -452,6 +456,10 @@ ARDOUR::init (bool use_windows_vst, bool try_optimization, const char* localedir
 	}
 #endif
 
+#ifdef HAVE_FFTW35F
+	fftwf_make_planner_thread_safe ();
+#endif
+
 	if (!PBD::init()) return false;
 
 #if ENABLE_NLS

libs/ardour/wscript

@@ -329,6 +329,9 @@ def configure(conf):
     autowaf.check_pkg(conf, 'libcurl', uselib_store='CURL',
                       atleast_version='7.0.0')
 
+    autowaf.check_pkg(conf, 'fftw3f', uselib_store='FFTW35F',
+                      atleast_version='3.3.5', mandatory=False)
+
     # controls whether we actually use it in preference to soundtouch
     # Note: as of 2104, soundtouch (WSOLA) has been out-of-use for years.
     conf.define('USE_RUBBERBAND', 1)

libs/audiographer/wscript

@@ -37,7 +37,6 @@ def configure(conf):
     autowaf.check_pkg(conf, 'samplerate', uselib_store='SAMPLERATE', atleast_version='0.1.7', mandatory=False)
     autowaf.check_pkg(conf, 'sndfile', uselib_store='SNDFILE', atleast_version='1.0.18', mandatory=False)
     autowaf.check_pkg(conf, 'fftw3f', uselib_store='FFTW3F', mandatory=True)
-    autowaf.check_pkg(conf, 'fftw3f', uselib_store='FFTW35F', atleast_version='3.3.5', mandatory=False)
 
     # Boost headers
     autowaf.check_header(conf, 'cxx', 'boost/shared_ptr.hpp')