Change PREFIX and LIBDIR to lowercase

This is the standard name.

Make.inc

@@ -4,8 +4,8 @@ OS := $(shell uname)
 VERSION = 0.1.0
 VERSION_SPLIT = $(subst ., , $(VERSION))
 DESTDIR =
-PREFIX = /usr/local
-libdir = $(PREFIX)/lib
+prefix = /usr/local
+libdir = $(prefix)/lib
 
 FC = gfortran
 FFLAGS += -O3

Makefile

@@ -43,6 +43,6 @@ distclean:
 
 install: all
 	mkdir -p $(DESTDIR)$(libdir)
-	mkdir -p $(DESTDIR)$(PREFIX)/include
+	mkdir -p $(DESTDIR)$(prefix)/include
 	cp -a libopenlibm.$(SHLIB_EXT)* libopenlibm.a $(DESTDIR)$(libdir)/
-	cp -a src/openlibm.h $(DESTDIR)$(PREFIX)/include/
+	cp -a src/openlibm.h $(DESTDIR)$(prefix)/include/