GUI: try using FFTW for per-chan osc wave center

not reliable yet

extern/fftw/threads/f77api.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2003, 2007-14 Matteo Frigo
+ * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#include "api/api.h"
+
+/* if F77_FUNC is not defined, then we don't know how to mangle identifiers
+   for the Fortran linker, and we must omit the f77 API. */
+#if defined(F77_FUNC) || defined(WINDOWS_F77_MANGLING)
+
+#include "api/x77.h"
+
+#define F77(a, A) F77x(x77(a), X77(A))
+
+#ifndef WINDOWS_F77_MANGLING
+
+#if defined(F77_FUNC)
+#  define F77x(a, A) F77_FUNC(a, A)
+#  include "f77funcs.h"
+#endif
+
+#if defined(F77_FUNC_) && !defined(F77_FUNC_EQUIV)
+#  undef F77x
+#  define F77x(a, A) F77_FUNC_(a, A)
+#  include "f77funcs.h"
+#endif
+
+#else /* WINDOWS_F77_MANGLING */
+
+/* Various mangling conventions common (?) under Windows. */
+
+/* g77 */
+#  define WINDOWS_F77_FUNC(a, A) a ## __
+#  define F77x(a, A) WINDOWS_F77_FUNC(a, A)
+#  include "f77funcs.h"
+
+/* Intel, etc. */
+#  undef WINDOWS_F77_FUNC
+#  define WINDOWS_F77_FUNC(a, A) a ## _
+#  include "f77funcs.h"
+
+/* Digital/Compaq/HP Visual Fortran, Intel Fortran.  stdcall attribute
+   is apparently required to adjust for calling conventions (callee
+   pops stack in stdcall).  See also:
+       http://msdn.microsoft.com/library/en-us/vccore98/html/_core_mixed.2d.language_programming.3a_.overview.asp
+*/
+#  undef WINDOWS_F77_FUNC
+#  if defined(__GNUC__)
+#    define WINDOWS_F77_FUNC(a, A) __attribute__((stdcall)) A
+#  elif defined(_MSC_VER) || defined(_ICC) || defined(_STDCALL_SUPPORTED)
+#    define WINDOWS_F77_FUNC(a, A) __stdcall A
+#  else
+#    define WINDOWS_F77_FUNC(a, A) A /* oh well */
+#  endif
+#  include "f77funcs.h"
+
+#endif /* WINDOWS_F77_MANGLING */
+
+#endif				/* F77_FUNC */