dnl future trouble.
dnl ===========================================================================
+dnl GINAC_HEADER_GETVAL(NAME,FILE)
+dnl ----------------------------
+dnl Expand at autoconf time to the value of a "#define NAME" from the given
+dnl FILE. The regexps here aren't very rugged, but are enough for us.
+dnl /dev/null as a parameter prevents a hang if $2 is accidentally omitted.
+dnl (shamelessly ripped from GMP, and changed prefix to GINAC_).
+
+define(GINAC_HEADER_GETVAL,
+[patsubst(patsubst(
+esyscmd([grep "^#define $1 " $2 /dev/null 2>/dev/null]),
+[^.*$1[ ]+],[]),
+[[
+ ]*$],[])])
+define(GINAC_GET_VERSION,
+[GINAC_HEADER_GETVAL(GINACLIB_$1_VERSION,[ginac/version.h])])
+define(GINAC_GET_LTVERSION,
+[GINAC_HEADER_GETVAL(GINAC_LT_$1,[ginac/version.h])])
+
dnl Usage: GINAC_STD_CXX_HEADERS
dnl Check for standard C++ headers, bail out if something is missing.
AC_DEFUN([GINAC_STD_CXX_HEADERS], [