Remove line breaks in make check.

make prints what it sees verbatim, linebreaks, backslashes, and all.
This kind of breaks logging output.

Makefile

@@ -40,9 +40,7 @@ install: all
 	install -Dt ${DESTDIR}/usr/lib/ libguile-gumbo.so
 
 check: all
-	env GUILE_LOAD_PATH=$$PWD \
-		GUILE_LOAD_COMPILED_PATH=$$PWD/ccache \
-		guile -s tests.scm
+	env GUILE_LOAD_PATH=$$PWD GUILE_LOAD_COMPILED_PATH=$$PWD/ccache guile -s tests.scm
 
 clean:
 	-rm *.o