configure.ac: use AC_SEARCH_LIBS instead of AC_CHECK_LIB
configure.ac: use AC_SEARCH_LIBS instead of AC_CHECK_LIB

AC_SEARCH_LIBS does exactly what we need here: check if a function is
available; if not, check if it's available in the specified library,
and add it to LIBS.

psych0tik/libmpdclient2,jagleeso/libmpdclient,yusiwen/libmpdclient,yusiwen/libmpdclient,jagleeso/libmpdclient,cmende/libmpdclient,psych0tik/libmpdclient2,cmende/libmpdclient,jwise/libmpdclient,sl0th/libmpdclient,cmende/libmpdclient,sl0th/libmpdclient,sl0th/libmpdclient,yusiwen/libmpdclient,jwise/libmpdclient,jwise/libmpdclient,jagleeso/libmpdclient