diff -up qclib-1.3.1/Makefile.docdir qclib-1.3.1/Makefile
--- qclib-1.3.1/Makefile.docdir	2017-10-24 07:02:42.000000000 +0200
+++ qclib-1.3.1/Makefile	2017-12-04 14:15:08.000000000 +0100
@@ -6,6 +6,7 @@
 #     bugfix: Bugfixes only
 VERSION = 1.4.1
 VERM    = $(shell echo $(VERSION) | cut -d '.' -f 1)
+DOCDIR ?= /usr/share/doc/packages/
 CFLAGS ?= -g -Wall -O2
 CFILES  = query_capacity.c query_capacity_data.c query_capacity_sysinfo.c query_capacity_ocf.c \
           query_capacity_hypfs.c query_capacity_sthyi.c
@@ -69,16 +70,16 @@ install: libqc.a libqc.so.$(VERSION)
 	ln -sr $(DESTDIR)/usr/lib64/libqc.so.$(VERSION) $(DESTDIR)/usr/lib64/libqc.so.$(VERM)
 	ln -sr $(DESTDIR)/usr/lib64/libqc.so.$(VERSION) $(DESTDIR)/usr/lib64/libqc.so
 	install -Dm 644 query_capacity.h $(DESTDIR)/usr/include/query_capacity.h
-	install -Dm 644 README $(DESTDIR)/usr/share/doc/packages/qclib/README
-	install -Dm 644 LICENSE $(DESTDIR)/usr/share/doc/packages/qclib/LICENSE
+	install -Dm 644 README $(DESTDIR)/$(DOCDIR)/qclib/README
+	install -Dm 644 LICENSE $(DESTDIR)/$(DOCDIR)/qclib/LICENSE
 
 installdoc: doc
 	echo "  INSTALLDOC"
-	install -dm 755 $(DESTDIR)/usr/share/doc/packages/qclib/html
-	cp -r html/* $(DESTDIR)/usr/share/doc/packages/qclib/html
-	chmod 644 $(DESTDIR)/usr/share/doc/packages/qclib/html/search/*
-	chmod 644 $(DESTDIR)/usr/share/doc/packages/qclib/html/*
-	chmod 755 $(DESTDIR)/usr/share/doc/packages/qclib/html/search
+	install -dm 755 $(DESTDIR)/$(DOCDIR)/qclib/html
+	cp -r html/* $(DESTDIR)/$(DOCDIR)/qclib/html
+	chmod 644 $(DESTDIR)/$(DOCDIR)/qclib/html/search/*
+	chmod 644 $(DESTDIR)/$(DOCDIR)/qclib/html/*
+	chmod 755 $(DESTDIR)/$(DOCDIR)/qclib/html/search
 
 clean:
 	echo "  CLEAN"