--- Makefile.orig	2013-09-27 10:55:28.000000000 +0200
+++ Makefile	2013-12-29 21:49:45.000000000 +0100
@@ -585,7 +585,7 @@ HAVE_UNUSED=
 
 #INCDIR= /usr/local/include
 #INCDIR= /dev/env/DJDIR/include
-INCDIR= /usr/include
+INCDIR= ${PREFIX}/include
 
 # Where to install calc related things
 #
@@ -624,15 +624,15 @@ INCDIR= /usr/include
 #
 #BINDIR= /usr/local/bin
 #BINDIR= /dev/env/DJDIR/bin
-BINDIR= /usr/bin
+BINDIR= ${PREFIX}/bin
 
 #LIBDIR= /usr/local/lib
 #LIBDIR= /dev/env/DJDIR/lib
-LIBDIR= /usr/lib
+LIBDIR= ${PREFIX}/lib
 
 #CALC_SHAREDIR= /usr/local/lib/calc
 #CALC_SHAREDIR= /dev/env/DJDIR/share/calc
-CALC_SHAREDIR= /usr/share/calc
+CALC_SHAREDIR= ${PREFIX}/share/calc
 
 # NOTE: Do not set CALC_INCDIR to /usr/include or /usr/local/include!!!
 #	Always be sure that the CALC_INCDIR path ends in /calc to avoid
@@ -699,7 +699,7 @@ SCRIPTDIR= ${BINDIR}/cscript
 #
 # If in doubt, use T=
 #
-T=
+T=${DESTDIR}
 
 # where man pages are installed
 #
@@ -710,7 +710,7 @@ T=
 #MANDIR=
 #MANDIR= /usr/local/man/man1
 #MANDIR= /usr/man/man1
-MANDIR= /usr/share/man/man1
+MANDIR= ${PREFIX}/man/man1
 #MANDIR= /dev/env/DJDIR/man/man1
 #MANDIR= /usr/man/u_man/man1
 #MANDIR= /usr/contrib/man/man1
@@ -837,14 +837,14 @@ CALCRC= ${CALC_SHAREDIR}/startup:~/.calc
 #
 # If in doubt, set USE_READLINE, READLINE_LIB and READLINE_INCLUDE to nothing.
 #
-USE_READLINE=
-#USE_READLINE= -DUSE_READLINE
+#USE_READLINE=
+USE_READLINE= -DUSE_READLINE
 #
-READLINE_LIB=
-READLINE_EXTRAS=
+#READLINE_LIB=
+#READLINE_EXTRAS=
 #
-#READLINE_LIB= -lreadline
-#READLINE_EXTRAS= -lhistory -lncurses
+READLINE_LIB= -lreadline
+READLINE_EXTRAS= -lhistory -lncurses
 #
 #READLINE_LIB= -L/usr/gnu/lib -lreadline
 #READLINE_EXTRAS= -lhistory -lncurses
@@ -869,7 +869,7 @@ READLINE_INCLUDE=
 #CALCPAGER= more
 #CALCPAGER= pg
 #CALCPAGER= cat
-CALCPAGER= less
+#CALCPAGER= less
 #CALCPAGER= less.exe -ci
 
 # Debug/Optimize options for ${CC} and ${LCC}
@@ -978,8 +978,8 @@ CALC_ENV= CALCPATH=./cal LD_LIBRARY_PATH
 # MKDIR_ARG= -p			# use mkdir -p when creating paths
 # MKDIR_ARG=			# use if system does not understand mkdir -p
 #
-MKDIR_ARG= -p
-#MKDIR_ARG=
+#MKDIR_ARG= -p
+MKDIR_ARG=
 
 # Some out of date operating systems require/want an executable to
 # end with a certain file extension.  Some compiler systems such as
@@ -1012,35 +1012,36 @@ LIB_EXT_VE= ${LIB_EXT}.${VE}
 
 # standard utilities used during make
 #
-SHELL= /bin/sh
+#SHELL= /bin/sh
 LANG= C
-MAKE= make
+#MAKE= make
 AWK= awk
-SED= sed
+#SED= sed
 DIFF= diff
 GREP= egrep
 SORT= sort
 TEE= tee
 CTAGS= ctags
-CHMOD= chmod
+#CHMOD= chmod
 FMT= fmt
 XARGS= xargs
 CMP= cmp
-MKDIR= mkdir
+#MKDIR= mkdir
 SPLINT= splint
 SPLINT_OPTS=
-RM= rm
-TOUCH= touch
+#RM= rm
+#TOUCH= touch
 RMDIR= rmdir
-CP= cp
-MV= mv
+#CP= cp
+#MV= mv
 CO= co
 AR= ar
-TRUE= true
-CAT= cat
+#TRUE= true
+#CAT= cat
 COL= col
-LN= ln
-LDCONFIG= ldconfig
+#LN= ln
+#LDCONFIG= ldconfig
+LDCONFIG=
 # assume the X11 makedepend tool for the depend rule
 MAKEDEPEND= makedepend
 STRIP= strip
@@ -1248,13 +1249,15 @@ LIBCUSTCALC_STATIC=
 #
 CCWARN= -Wall -W -Wno-comment
 CCWERR=
-CCOPT= ${DEBUG}
+#CCOPT= ${DEBUG}
+CCOPT=
 CCMISC=
 #
-LCC= gcc
-CC= ${PURIFY} ${LCC} ${CCWERR}
+LCC= ${CC}
+#CC= ${PURIFY} ${LCC} ${CCWERR}
 #
-MAKE= gmake
+#MAKE= gmake
+MAKE= ${GMAKE}
 #
 endif
 
@@ -1516,7 +1519,8 @@ ICFLAGS= ${COMMON_CFLAGS} ${CC_STATIC}
 else
 ICFLAGS= ${COMMON_CFLAGS} ${CC_SHARE}
 endif
-CFLAGS= ${ICFLAGS} ${CCOPT}
+#CFLAGS= ${ICFLAGS} ${CCOPT}
+CFLAGS+= ${ICFLAGS} ${CCOPT}
 
 # Required flags to link files for calc
 #