diff --git a/Make.inc b/Make.inc
index 64cdc5b..6b99266 100644
--- a/Make.inc
+++ b/Make.inc
@@ -4,8 +4,9 @@ OS := $(shell uname)
 VERSION = 0.1.0
 VERSION_SPLIT = $(subst ., , $(VERSION))
 DESTDIR =
-PREFIX = /usr/local
-libdir = $(PREFIX)/lib
+prefix = /usr/local
+libdir = $(prefix)/lib
+includedir = $(prefix)/include
 
 FC = gfortran
 FFLAGS += -O3
@@ -69,28 +70,29 @@ override OS=WINNT
 endif
 #keep these if statements these separate
 ifeq ($(OS), WINNT)
+SHLIB_EXT = dll
+SONAME_FLAG = -soname
 CFLAGS_add+=-nodefaultlibs
 FFLAGS+=-nodefaultlibs
 endif
 
 ifeq ($(OS), Linux)
 SHLIB_EXT = so
+SONAME_FLAG = -soname
 CFLAGS_add+=-fPIC
 FFLAGS+=-fPIC
 endif
 
 ifeq ($(OS), FreeBSD)
 SHLIB_EXT = so
+SONAME_FLAG = -soname
 CFLAGS_add+=-fPIC
 FFLAGS+=-fPIC
 endif
 
 ifeq ($(OS), Darwin)
 SHLIB_EXT = dylib
+SONAME_FLAG = -install_name
 CFLAGS_add+=-fPIC
 FFLAGS+=-fPIC
 endif
-
-ifeq ($(OS), WINNT)
-SHLIB_EXT = dll
-endif
diff --git a/Makefile b/Makefile
index 0db517b..26c8bd5 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,7 @@ all: libopenlibm.a libopenlibm.$(SHLIB_EXT)
 libopenlibm.a: $(OBJS)  
 	$(AR) -rcs libopenlibm.a $(OBJS)
 libopenlibm.$(SHLIB_EXT): $(OBJS)
-	$(FC) -shared $(OBJS) $(LDFLAGS) -o libopenlibm.$(SHLIB_EXT).$(VERSION)
+	$(FC) -shared $(OBJS) $(LDFLAGS) -Wl,$(SONAME_FLAG),libopenlibm.$(SHLIB_EXT).$(VERSION) -o libopenlibm.$(SHLIB_EXT).$(VERSION)
 	ln -s libopenlibm.$(SHLIB_EXT).$(VERSION) libopenlibm.$(SHLIB_EXT).$(word 1,$(VERSION_SPLIT)).$(word 2,$(VERSION_SPLIT))
 	ln -s libopenlibm.$(SHLIB_EXT).$(VERSION) libopenlibm.$(SHLIB_EXT).$(word 1,$(VERSION_SPLIT))
 	ln -s libopenlibm.$(SHLIB_EXT).$(VERSION) libopenlibm.$(SHLIB_EXT)
@@ -43,6 +43,6 @@ distclean:
 
 install: all
 	mkdir -p $(DESTDIR)$(libdir)
-	mkdir -p $(DESTDIR)$(PREFIX)/include
+	mkdir -p $(DESTDIR)$(includedir)
 	cp -a libopenlibm.$(SHLIB_EXT)* libopenlibm.a $(DESTDIR)$(libdir)/
-	cp -a src/openlibm.h $(DESTDIR)$(PREFIX)/include/
+	cp -a src/openlibm.h $(DESTDIR)$(includedir)/