For PR798:
Have configure find the "dotty" program and adjust configuration.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28674 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 2c2f2ce..0225a3d 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -352,6 +352,8 @@
 AC_PATH_PROG(RM,   [rm],   [rm])
 AC_PATH_PROG(SED,  [sed],  [sed])
 AC_PATH_PROG(TAR,  [tar],  [gtar])
+
+dnl Looking for misc. graph plotting software
 AC_PATH_PROG(GRAPHVIZ, [Graphviz], [echo Graphviz])
 if test "$GRAPHVIZ" != "echo Graphviz" ; then
   AC_DEFINE([HAVE_GRAPHVIZ],[1],[Define if the Graphviz program is available])
@@ -364,6 +366,12 @@
   AC_DEFINE_UNQUOTED([LLVM_PATH_GV],"$GV",
    [Define to path to gv program if found or 'echo gv' otherwise])
 fi
+AC_PATH_PROG(DOTTY, [dotty], [echo dotty])
+if test "$DOTTY" != "echo dotty" ; then
+  AC_DEFINE([HAVE_DOTTY],[1],[Define if the dotty program is available])
+  AC_DEFINE_UNQUOTED([LLVM_PATH_DOTTY],"$DOTTY",
+   [Define to path to dotty program if found or 'echo dotty' otherwise])
+fi
 
 dnl Look for a sufficiently recent version of Perl.
 LLVM_PROG_PERL([5.006])