diff -Nurd calc-2.13.0.1.orig/Makefile calc-2.13.0.1/Makefile
--- calc-2.13.0.1.orig/Makefile	2021-04-11 06:24:51.000000000 -0400
+++ calc-2.13.0.1/Makefile	2021-05-29 05:26:55.000000000 -0400
@@ -157,7 +157,7 @@
 #
 # If in doubt, leave TERMCONTROL empty.
 #
-TERMCONTROL=
+TERMCONTROL= -DUSE_TERMIOS
 #TERMCONTROL= -DUSE_TERMIOS
 #TERMCONTROL= -DUSE_TERMIO
 #TERMCONTROL= -DUSE_SGTTY
@@ -686,7 +686,7 @@
 ifeq ($(target),Darwin)
 
 # default INCDIR for macOS
-INCDIR= $(shell xcrun --show-sdk-path --sdk macosx)/usr/include
+INCDIR= ${PREFIX}/include
 
 else
 #endif	/* end of skip for non-Gnu makefiles */
@@ -828,7 +828,7 @@
 CUSTOMCALDIR= ${CALC_SHAREDIR}/custom
 CUSTOMHELPDIR= ${CALC_SHAREDIR}/custhelp
 CUSTOMINCDIR= ${CALC_INCDIR}/custom
-SCRIPTDIR= ${BINDIR}/cscript
+SCRIPTDIR= ${BINDIR}
 
 # T - top level directory under which calc will be installed
 #
@@ -959,7 +959,7 @@
 # lines below.
 #
 #NROFF= nroff
-NROFF=
+NROFF= nroff
 #NROFF= groff
 NROFF_ARG= -man
 #NROFF_ARG= -mandoc
@@ -1033,11 +1033,11 @@
 #
 # If in doubt, set USE_READLINE, READLINE_LIB and READLINE_INCLUDE to nothing.
 #
-USE_READLINE=
+USE_READLINE= -DUSE_READLINE
 #USE_READLINE= -DUSE_READLINE
 #
-READLINE_LIB=
-READLINE_EXTRAS=
+READLINE_LIB= -L${PREFIX}/lib -lreadline
+READLINE_EXTRAS= -lhistory -lncurses
 #
 #READLINE_LIB= -lreadline
 #READLINE_EXTRAS= -lhistory -lncurses
@@ -1063,7 +1063,7 @@
 #READLINE_LIB= -L${PREFIX}/opt/readline/lib -lreadline
 #READLINE_EXTRAS= -lhistory -lncurses
 #
-READLINE_INCLUDE=
+READLINE_INCLUDE= -I${PREFIX}/include
 #READLINE_INCLUDE= -I/usr/gnu/include
 #READLINE_INCLUDE= -I${PREFIX}/include
 
@@ -2581,14 +2581,14 @@
 
 hist.o: hist.c ${MAKE_FILE} ${LOC_MKF}
 	${CC} ${CFLAGS} ${TERMCONTROL} ${USE_READLINE} ${READLINE_INCLUDE} \
-	    -c hist.c
+	    -c hist.c ${CPPFLAGS}
 
 seed.o: seed.c ${MAKE_FILE} ${LOC_MKF}
 	${CC} ${CFLAGS} ${WNO_IMPLICT} ${WNO_ERROR_LONG_LONG} \
-	    ${WNO_LONG_LONG} -c seed.c
+	    ${WNO_LONG_LONG} -c seed.c ${CPPFLAGS}
 
 file.o: file.c ${MAKE_FILE} ${LOC_MKF}
-	${CC} ${CFLAGS} ${WNO_ERROR_LONG_LONG} ${WNO_LONG_LONG} -c file.c
+	${CC} ${CFLAGS} ${WNO_ERROR_LONG_LONG} ${WNO_LONG_LONG} -c file.c ${CPPFLAGS}
 
 ###
 #
@@ -5100,7 +5100,7 @@
 	${Q}# NOTE: The this makefile installs libcustcalc${LIB_EXT_VERSION}
 	${Q}#       because we only want to perform one ${LDCONFIG} for both
 	${Q}#       libcalc${LIB_EXT_VERSION} and libcustcalc${LIB_EXT_VERSION}.
-	-${Q} if ${CMP} -s libcalc${LIB_EXT_VERSION} \
+	-${Q} if [ ! -e libcalc${LIB_EXT_VERSION} ]; then ${TRUE}; elif ${CMP} -s libcalc${LIB_EXT_VERSION} \
 		     ${T}${LIBDIR}/libcalc${LIB_EXT_VERSION} && \
 	   ${CMP} -s custom/libcustcalc${LIB_EXT_VERSION} \
 		     ${T}${LIBDIR}/libcustcalc${LIB_EXT_VERSION}; then \
diff -Nurd calc-2.13.0.1.orig/custom/Makefile calc-2.13.0.1/custom/Makefile
--- calc-2.13.0.1.orig/custom/Makefile	2021-04-17 02:53:22.000000000 -0400
+++ calc-2.13.0.1/custom/Makefile	2021-05-29 05:33:05.000000000 -0400
@@ -1305,7 +1305,7 @@
 ##
 
 c_sysinfo.o: c_sysinfo.c ${MAKE_FILE}
-	${CC} ${CFLAGS} c_sysinfo.c -c
+	${CC} ${CFLAGS} c_sysinfo.c -c ${CPPFLAGS}
 
 ##
 #