add raptor2 compatibility for lrdf

[schivmeister]

Hello fellow drummers

Hydrogen will fail to build with lrdf if raptor2 is installed:

/usr/include/lrdf.h:8:20: fatal error: raptor.h: No such file or directory

This is obviously because the includes are in a different path for raptor2, and although cmake (by way of pkg-config, whether or not LRDF is ON) populates the relevant env vars, they are not used:

[hydrogen-0.9.6]$ grep -Ri 'raptor2'
CMakeCache.txt:LRDF_CFLAGS:INTERNAL=-I/usr/include/raptor2
CMakeCache.txt:LRDF_INCLUDE_DIRS:INTERNAL=/usr/include/raptor2
CMakeCache.txt:LRDF_STATIC_CFLAGS:INTERNAL=-I/usr/include/raptor2
CMakeCache.txt:LRDF_STATIC_INCLUDE_DIRS:INTERNAL=/usr/include/raptor2
CMakeCache.txt:LRDF_STATIC_LDFLAGS:INTERNAL=-llrdf;-lraptor2;-lcrypto
CMakeCache.txt:LRDF_STATIC_LIBRARIES:INTERNAL=lrdf;raptor2;crypto

This is actually an old issue and I have propagated fixes to some other upstream projects since 2011, but I never got around to reporting to hydrogen.

Now that the buildsystem changed to cmake, my old patch no longer works. The fix is buildsystem-dependent, so here I propose a simple cmake-friendly modification:

--- hydrogen-0.9.6.orig/CMakeLists.txt
+++ hydrogen-0.9.6/CMakeLists.txt
@@ -193,6 +193,9 @@
 FIND_HELPER(PULSEAUDIO pulseaudio pulse/pulseaudio.h pulse)
 FIND_HELPER(LASH lash-1.0 lash/lash.h lash)
 FIND_HELPER(LRDF lrdf lrdf.h lrdf)
+IF(LRDF_FOUND)
+    include_directories(${LRDF_INCLUDE_DIRS})
+ENDIF(LRDF_FOUND)
 FIND_HELPER(RUBBERBAND rubberband RubberBandStretcher.h rubberband)
 FIND_HELPER(CPPUNIT cppunit cppunit/TestCase.h cppunit)
 # CHECK FOR Qt4

That should be it -- keep up the good work, guys!

[mauser]

Hi Ray!

I'm trying to reproduce the situation on my Ubuntu, but i couldn't make it happen.. Here liblrdf0-dev depends on libraptor1-dev, which provides /usr/include/raptor.h. So it is guaranteed that the file is there. What is the situation on your system?

[schivmeister]

This is simply for compatibility with systems that have lrdf + raptor2 (as per issue title). In this case lrdf.h includes raptor.h, which does not exist on the system. What exists on the system is raptor2, which includes both versions of the header in its own directory (/usr/include/raptor2). Pkg-config picks this up nicely, but with cmake you have to tell it what information to use for the found dependency (lrdf.h).

[mauser]

Thanks Ray, this is now in the repository.