Fix artsc-config script to return valid include directory

Fix FTBFS on openbsd
This resolves Bug 2160

Signed-off-by: François Andriot <francois.andriot@free.fr>
(cherry picked from commit 775e3e4645)

artsc/CMakeLists.txt

@@ -17,8 +17,10 @@ add_definitions( -DCOMPILING_ARTSC )
 set( prefix ${CMAKE_INSTALL_PREFIX} )
 set( exec_prefix $prefix )
 set( libdir ${LIB_INSTALL_DIR} )
-set( includedir ${INCLUDE_INSTALL_DIR} )
-set( LIBDL -l${DL_LIBRARIES} )
+set( includedir ${CMAKE_INSTALL_PREFIX}/include/artsc )
+if( NOT "${DL_LIBRARIES}" STREQUAL "" )
+  set( LIBDL -l${DL_LIBRARIES} )
+endif( )
 set( USE_THREADS )
 set( LIBPTHREAD ${CMAKE_THREAD_LIBS_INIT} )
 foreach( LIB ${GTHREAD2_LIBRARIES} )
@@ -57,7 +59,7 @@ include_directories(
 # FIXME: DESTINATION is currently a workaround
 install( FILES
     artsc.h ${CMAKE_CURRENT_BINARY_DIR}/artsc_export.h
-  DESTINATION ${CMAKE_INSTALL_PREFIX}/include/artsc )
+  DESTINATION ${includedir} )
 
 
 ##### artsdsp (shared lib) ######################

artsc/artsc-config.in

@@ -18,7 +18,7 @@ EOH
 prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
-includedir=@includedir@c
+includedir=@includedir@
 libdl=@LIBDL@
 
 flags=""