1 files changed, 40 insertions, 0 deletions
diff --git a/m4/macros/expand_cpp_hex.m4 b/m4/macros/expand_cpp_hex.m4
new file mode 100644
index 000000000000..0c7a9e421abd
--- /dev/null
+++ b/m4/macros/expand_cpp_hex.m4
@@ -0,0 +1,40 @@
+dnl ######################################################################
+dnl Expand the value of a CPP macro into a printable hex number.
+dnl Takes: header, macro, [action-if-found, [action-if-not-found]]
+dnl It runs the header through CPP looking for a match between the macro
+dnl and a string pattern, and if sucessful, it prints the string value out.
+AC_DEFUN([AMU_EXPAND_CPP_HEX],
+[
+# we are looking for a regexp of a string
+AC_EGREP_CPP(0x,
+[$1]
+$2,
+value="notfound"
+AC_TRY_RUN(
+[
+[$1]
+main(argc)
+int argc;
+{
+#ifdef $2
+if (argc > 1)
+  printf("0x%x", $2);
+exit(0);
+#else
+# error no such option $2
+#endif
+exit(1);
+}], value=`./conftest dummy 2>>config.log`, value="notfound", value="notfound")
+,
+value="notfound"
+)
+if test "$value" = notfound
+then
+  :
+  $4
+else
+  :
+  $3
+fi
+])
+dnl ======================================================================