+ifeq ($(MAC_OS_X),1)
+LIBRARY_SUFFIX = dylib
+# On OS X, library version numbers go before suffix.
+LINKER_NAME = libnotmuch.$(LIBRARY_SUFFIX)
+SONAME = libnotmuch.$(LIBNOTMUCH_VERSION_MAJOR).$(LIBRARY_SUFFIX)
+LIBNAME = libnotmuch.$(LIBNOTMUCH_VERSION_MAJOR).$(LIBNOTMUCH_VERSION_MINOR).$(LIBNOTMUCH_VERSION_RELEASE).$(LIBRARY_SUFFIX)
+LIBRARY_LINK_FLAG = -Wl,-dylib_install_name -Wl,$(SONAME)
+else
+LIBRARY_SUFFIX = so
+LINKER_NAME = libnotmuch.$(LIBRARY_SUFFIX)