diff --git a/Makefile b/Makefile
index db82b721..07acbe3a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
-DC = dmd
-DFLAGS = -w -g -ofonedrive -O -L-lcurl -L-lsqlite3 -L-ldl -J.
-PREFIX = /usr/local
+DC ?= dmd
+DFLAGS += -w -g -ofonedrive -O -L-lcurl -L-lsqlite3 -L-ldl -J.
+PREFIX ?= /usr/local
 DOCDIR = $(PREFIX)/share/doc/onedrive
 MANDIR = $(PREFIX)/share/man/man1
 DOCFILES = README.md README.Office365.md config LICENSE CHANGELOG.md