Added a test for readline.h and eventually enabled use of libreadline

test/configure_ac.txt

@@ -7,7 +7,7 @@ AC_CANONICAL_TARGET
 
 AM_INIT_AUTOMAKE([subdir-objects])
 
-# A dummy demanded by libburn sources, but unused by xorriso
+dnl A dummy demanded by libburn sources, but unused by xorriso
 BURN_MAJOR_VERSION=0
 BURN_MINOR_VERSION=0
 BURN_MICRO_VERSION=0
@@ -68,6 +68,17 @@ else
     CFLAGS="$CFLAGS -DDEBUG"
 fi
 
+
+dnl Check whether there is readline-devel and readline-runtime.
+dnl If not, erase this macro which would enable use of readline(),add_history()
+READLINE_DEF="-DXorriso_with_readlinE"
+dnl The empty yes case obviously causes -lreadline to be linked
+AC_CHECK_HEADER(readline/readline.h, AC_CHECK_LIB(readline, readline, , READLINE_DEF= ), READLINE_DEF= )
+dnl The X= in the yes case prevents that -lreadline gets linked twice
+AC_CHECK_HEADER(readline/history.h, AC_CHECK_LIB(readline, add_history, X= , READLINE_DEF= ), READLINE_DEF= )
+AC_SUBST(READLINE_DEF)
+
+
 AC_CONFIG_FILES([
 	Makefile
 	version.h

test/xorriso_makefile_am.txt

@@ -18,7 +18,7 @@ xorriso_xorriso_CPPFLAGS = -I./libburn -I./libisofs -I./libisoburn -I./xorriso
 
 # No readline in the vanilla version because the necessary headers
 # are in a separate readline-development package.
-xorriso_xorriso_CFLAGS = -DXorriso_standalonE -DXorriso_with_maiN -DXorriso_with_regeX
+xorriso_xorriso_CFLAGS = -DXorriso_standalonE -DXorriso_with_maiN -DXorriso_with_regeX $(READLINE_DEF)
 
 xorriso_xorriso_LDADD = $(THREAD_LIBS)