Fix a compilation error and tidy up some messages.

FFTConvolver/convolver.cpp

@@ -5,8 +5,11 @@
 #include "FFTConvolver.h"
 #include "Utilities.h"
 
-extern "C" void die(const char *format, ...);
-extern "C" void debug(int level, const char *format, ...);
+extern "C" void _die(const char *filename, const int linenumber, const char *format, ...);
+extern "C" void _debug(const char *filename, const int linenumber, int level, const char *format, ...);
+
+#define die(...) _die(__FILE__, __LINE__, __VA_ARGS__)
+#define debug(...) _debug(__FILE__, __LINE__, __VA_ARGS__)
 
 static fftconvolver::FFTConvolver convolver_l;
 static fftconvolver::FFTConvolver convolver_r;

configure.ac

@@ -298,7 +298,7 @@ AC_ARG_WITH(convolution, [  --with-convolution = choose audio DSP convolution su
   REQUESTED_CONVOLUTION=1
   AM_INIT_AUTOMAKE([subdir-objects])
   AC_DEFINE([CONFIG_CONVOLUTION], 1, [Needed by the compiler.])
-  AC_CHECK_LIB([sndfile], [sf_open], , AC_MSG_ERROR(Convolution support requires the sndfile library!))], )
+  AC_CHECK_LIB([sndfile], [sf_open], , AC_MSG_ERROR(Convolution support requires the sndfile library -- libsndfile1-dev suggested!))], )
 AM_CONDITIONAL([USE_CONVOLUTION], [test "x$REQUESTED_CONVOLUTION" = "x1"])
 
 # Look for dns_sd flag