diff --git a/documents/Makefile b/documents/Makefile
index d60c795..4b8db4a 100644
--- a/documents/Makefile
+++ b/documents/Makefile
@@ -28,10 +28,13 @@ all: $(HTML_FILES)
 
 # copy the created files to the destination directory (usually outside of this directory tree)
 install: $(TARGET_FILES)
-	@[ -z "$(CCD_BUILD_DIR)" ] && echo "CCD_BUILD_DIR must be defined! (this should be done by the parent Makefile)" >&2 && false
+	@if [ -z "$(CCD_BUILD_DIR)" ] ; \
+		then	echo "CCD_BUILD_DIR must be defined! (this should be done by the parent Makefile)" >&2 ; \
+			false ; \
+	  fi
 	@if [ ! -e "$(CCD_BUILD_DIR)" ] ; \
 		then	echo "CCD_BUILD_DIR ($(CCD_BUILD_DIR)) does not exist!" ; \
-			exit 1 ; \
+			false ; \
 	  fi
 	@cp -r _output/* "$(CCD_BUILD_DIR)/doku"