diff -u -r ../gnucap-20171003/apps/Make2.Debug ./apps/Make2.Debug
--- ../gnucap-20171003/apps/Make2.Debug	2017-10-04 00:50:49.000000000 +0200
+++ ./apps/Make2.Debug	2019-01-24 22:30:16.059909732 +0100
@@ -24,7 +24,7 @@
 # Standard base for g++, debugging, a little optimization
 # Running the program will give a spew of line markers for debugging.
 
-CCC = g++
+CCC = $(CXX)
 TARGET_EXT = .so
 
 CCFLAGS = \
diff -u -r ../gnucap-20171003/apps/Make2.g++ ./apps/Make2.g++
--- ../gnucap-20171003/apps/Make2.g++	2017-10-04 00:50:49.000000000 +0200
+++ ./apps/Make2.g++	2019-01-24 22:30:16.059909732 +0100
@@ -23,7 +23,7 @@
 
 # Standard base for g++.
 
-CCC = g++
+CCC = $(CXX)
 TARGET_EXT = .so
 
 CCFLAGS = \
diff -u -r ../gnucap-20171003/include/configure ./include/configure
--- ../gnucap-20171003/include/configure	2017-10-04 00:50:49.000000000 +0200
+++ ./include/configure	2019-01-24 22:30:16.059909732 +0100
@@ -22,7 +22,7 @@
 #----------------------------------------------------------------
 echo \# created by $PWD/$0. do not edit >Make2
 echo \#------------------------------------------------------------------------ >>Make2
-echo "CCC = c++" >>Make2
+echo "CCC = \$(CXX)" >>Make2
 echo "PREFIX = " $prefix >>Make2
 echo "" >>Make2
 
diff -u -r ../gnucap-20171003/lib/Make2.Debug ./lib/Make2.Debug
--- ../gnucap-20171003/lib/Make2.Debug	2017-10-04 00:50:49.000000000 +0200
+++ ./lib/Make2.Debug	2019-01-24 22:30:16.059909732 +0100
@@ -24,7 +24,7 @@
 # Standard base for g++, debugging, a little optimization
 # Running the program will give a spew of line markers for debugging.
 
-CCC = g++
+CCC = $(CXX)
 TARGET_EXT = .so
 
 CCFLAGS = \
diff -u -r ../gnucap-20171003/lib/Make2.g++ ./lib/Make2.g++
--- ../gnucap-20171003/lib/Make2.g++	2017-10-04 00:50:49.000000000 +0200
+++ ./lib/Make2.g++	2019-01-24 22:30:16.059909732 +0100
@@ -23,7 +23,7 @@
 
 # Standard base for g++.
 
-CCC = g++
+CCC = $(CXX)
 TARGET_EXT = .so
 
 CCFLAGS = \
diff -u -r ../gnucap-20171003/main/configure ./main/configure
--- ../gnucap-20171003/main/configure	2017-10-04 00:50:49.000000000 +0200
+++ ./main/configure	2019-01-24 22:31:37.649909149 +0100
@@ -26,7 +26,7 @@
 pkglibdir=$prefix/lib/gnucap
 
 # bug. this is not implemented consistently.
-CXX=${CXX-c++}
+CXX=${CXX}
 
 fill_template() {
 sed -e "s#@prefix@#$prefix#" \
@@ -48,7 +48,7 @@
 chmod +x gnucap-conf
 #----------------------------------------------------------------
 echo "CCFLAGS = \\" >Make.ccflags
-echo "-DUNIX -O2 -DNDEBUG -I. -I../include -I../../include -W" >>Make.ccflags
+echo "-DUNIX -O2 -DNDEBUG \$(CPPFLAGS) -I. -I../include -I../../include -W" >>Make.ccflags
 
 echo "LIBS = \\" >Make.libs
 echo "-lgnucap \\" >>Make.libs
@@ -59,10 +59,10 @@
 cat <<CAT_EOF >Make.sys
 #------------------------------------------------------------------------
 VPATH = .:..
-CCC = c++
+CCC = \$(CXX)
 TARGET_EXT =
 
-LDFLAGS = -rdynamic \
+LDFLAGS += -rdynamic \
 -L../../lib/O
 
 .SUFFIXES : .o .cc
diff -u -r ../gnucap-20171003/main/Make2.Debug ./main/Make2.Debug
--- ../gnucap-20171003/main/Make2.Debug	2017-10-04 00:50:49.000000000 +0200
+++ ./main/Make2.Debug	2019-01-24 22:30:16.059909732 +0100
@@ -24,7 +24,7 @@
 # Standard base for g++, debugging, no optimization
 # Running the program will give a spew of line markers for debugging.
 
-CCC = g++
+CCC = $(CXX)
 
 CCFLAGS = \
 -DUNIX  -g -O0 -I. -I../../include -DTRACE_UNTESTED \
diff -u -r ../gnucap-20171003/main/Make2.g++ ./main/Make2.g++
--- ../gnucap-20171003/main/Make2.g++	2017-10-04 00:50:49.000000000 +0200
+++ ./main/Make2.g++	2019-01-24 22:30:16.059909732 +0100
@@ -23,7 +23,7 @@
 
 # Standard base for g++.
 
-CCC = g++
+CCC = $(CXX)
 
 CCFLAGS = \
 -DUNIX -O3 -DNDEBUG -I. -I../include -I../../include -W
diff -u -r ../gnucap-20171003/modelgen/configure ./modelgen/configure
--- ../gnucap-20171003/modelgen/configure	2017-10-04 00:50:49.000000000 +0200
+++ ./modelgen/configure	2019-01-24 22:31:17.489909279 +0100
@@ -36,10 +36,10 @@
 cat <<CAT_EOF >Make.sys
 #------------------------------------------------------------------------
 VPATH = .:..
-CCC = c++
+CCC = \$(CXX)
 TARGET_EXT =
 
-LDFLAGS = -rdynamic \
+LDFLAGS += -rdynamic \
 -L../../lib/O
 
 .SUFFIXES : .o .cc
diff -u -r ../gnucap-20171003/modelgen/Make2.Debug ./modelgen/Make2.Debug
--- ../gnucap-20171003/modelgen/Make2.Debug	2017-10-04 00:50:49.000000000 +0200
+++ ./modelgen/Make2.Debug	2019-01-24 22:30:16.059909732 +0100
@@ -24,7 +24,7 @@
 # Standard base for g++, debugging, no optimization
 # Running the program will give a spew of line markers for debugging.
 
-CCC = g++
+CCC = $(CXX)
 
 CCFLAGS = \
 -DUNIX  -g -O0 -I. -I../../include -DTRACE_UNTESTED \
diff -u -r ../gnucap-20171003/modelgen/Make2.g++ ./modelgen/Make2.g++
--- ../gnucap-20171003/modelgen/Make2.g++	2017-10-04 00:50:49.000000000 +0200
+++ ./modelgen/Make2.g++	2019-01-24 22:30:16.059909732 +0100
@@ -23,7 +23,7 @@
 
 # Standard base for g++.
 
-CCC = g++
+CCC = $(CXX)
 
 CCFLAGS = \
 -DUNIX -O3 -DNDEBUG -I. -I../include -I../../include -W