Add check for kramdown so that both RONN and KRAMDOWN are set by configure script

Makefile.am

@@ -14,7 +14,6 @@ pkgconfig_DATA = espeak-ng.pc
 SHARED_VERSION=2:51:1 # = *.so.1.1.51
 
 MKDIR=mkdir -p
-KRAMDOWN=kramdown
 
 # -Wno-endif-labels : Needed to prevent warnings in ieee80.c.
 AM_CFLAGS = \

configure.ac

@@ -257,6 +257,8 @@ AC_CHECK_PROG(RONN, ronn, ronn, no)
 
 AM_CONDITIONAL(HAVE_RONN, [test ! x"$RONN" = xno])
 
+AC_CHECK_PROG(KRAMDOWN, kramdown, kramdown, no)
+
 dnl ================================================================
 dnl Extended dictionary checks.
 dnl ================================================================