Force automake to invoke the C (not C++) linker in kit/ when no C++ is in use.

git-svn-id: https://hamlib.svn.sourceforge.net/svnroot/hamlib/trunk@2989 7ae35d74-ebe9-4afe-98af-79ac388436b8

configure.ac

@@ -373,6 +373,7 @@ if test "${cf_with_cxx}" = "yes" ; then
   fi
 fi
 AM_CONDITIONAL(ENABLE_CXX, test x"${cf_with_cxx}" = "xyes")
+AM_CONDITIONAL(HAVE_USRP, test x"${cf_with_usrp}" = "xyes")
 
 
 PKG_CHECK_MODULES(LIBUSB, libusb >= 0.1, , 

kit/Makefile.am

@@ -1,11 +1,17 @@
 AM_CFLAGS = @LIBUSB_CFLAGS@
-AM_CXXFLAGS = @USRP_CFLAGS@
 
 # FIXME: compile usrp only if CXX available
 KITSRCLIST = elektor304.c drt1.c dwt.c usrp.c elektor507.c \
 	     dds60.c miniVNA.c si570avrusb.c
-if ENABLE_CXX
-KITSRCLIST += usrp_impl.cc
+
+if HAVE_USRP
+    AM_CXXFLAGS = @USRP_CFLAGS@
+    KITSRCLIST += usrp_impl.cc
+else
+    # automake gets confused and invokes the C++ linker via libtool regardless
+    # of whether or not HAVE_USRP enables the .cc source.  This override forces
+    # automake to invoke the C linker as no C++ is involved:
+    hamlib_kit_la_LINK = $(LINK) $(hamlib_kit_la_LDFLAGS)
 endif
 
 KITROTSRCLIST = pcrotor.c