+# libserialport is only needed for some hardware drivers. Disable the
+# respective drivers if it is not found.
+PKG_CHECK_MODULES([libserialport], [libserialport >= 0.1.0],
+ [have_libserialport="yes"; CFLAGS="$CFLAGS $libserialport_CFLAGS";
+ LIBS="$LIBS $libserialport_LIBS";
+ SR_PKGLIBS="$SR_PKGLIBS libserialport"],
+ [have_libserialport="no"; HW_AGILENT_DMM="no"; HW_APPA_55II="no";
+ HW_ATTEN_PPS3XXX="no"; HW_BRYMEN_DMM="no"; HW_CEM_DT_885X="no";
+ HW_CENTER_3XX="no"; HW_COLEAD_SLM="no"; HW_CONRAD_DIGI_35_CPU="no";
+ HW_FLUKE_DMM="no"; HW_GMC_MH_1X_2X="no"; HW_HAMEG_HMO="no"; HW_LINK_MSO19="no";
+ HW_MIC_985XX="no"; HW_NORMA_DMM="no"; HW_OLS="no";
+ HW_SERIAL_DMM="no"; HW_TELEINFO="no"; HW_TONDAJ_SL_814="no"])
+
+# Define HAVE_LIBSERIALPORT in config.h if we found libserialport.
+if test "x$have_libserialport" != "xno"; then
+ AC_DEFINE_UNQUOTED(HAVE_LIBSERIALPORT, [1],
+ [Specifies whether we have libserialport.])
+fi
+
+# Serial port helper code is only compiled in if libserialport was found.
+AM_CONDITIONAL(NEED_SERIAL, test "x$have_libserialport" != xno)
+
+PKG_CHECK_MODULES([librevisa], [librevisa >= 0.0.20130812],
+ [have_librevisa="yes"; CFLAGS="$CFLAGS $librevisa_CFLAGS";
+ LIBS="$LIBS $librevisa_LIBS";
+ SR_PKGLIBS="$SR_PKGLIBS librevisa"],
+ [have_librevisa="no"])
+
+# VISA SCPI backend is only compiled in if librevisa was found.
+AM_CONDITIONAL(NEED_VISA, test "x$have_librevisa" != xno)
+
+# Define HAVE_LIBREVISA in config.h if we found librevisa.
+if test "x$have_librevisa" != "xno"; then
+ AC_DEFINE_UNQUOTED(HAVE_LIBREVISA, [1],
+ [Specifies whether we have librevisa.])
+fi
+