diff --git a/ChangeLog b/ChangeLog
index 505523735..80dc4e410 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2004-03-21  Gonzalo Paniagua Javier <gonzalo@ximian.com>
+
+	* configure.in: if no C# compiler found, error out.
+
 2004-03-18  Mike Kestner  <mkestner@ximian.com>
 
 	* gdk/Makefile.am : generate glue
diff --git a/configure.in b/configure.in
index 22eafe626..7751968a5 100644
--- a/configure.in
+++ b/configure.in
@@ -60,20 +60,26 @@ PKG_CHECK_MODULES(MONO_DEPENDENCY, mono, has_mono=true, has_mono=false)
 
 if test "x$has_mono" = "xtrue"; then
 if test `uname -s` = "Darwin"; then
-	RUNTIME=`which mint`
-	CSC=`which mcs`
+	AC_PATH_PROG(RUNTIME, mint, no)
+	AC_PATH_PROG(CSC, mcs, no)
 else
-	RUNTIME=`which mono`
-	CSC=`which mcs`
+	AC_PATH_PROG(RUNTIME, mono, no)
+	AC_PATH_PROG(CSC, mcs, no)
 fi
 else
-AC_PATH_PROG(CSC, csc.exe, $PATH)
-if test x$CSC = ""; then
+AC_PATH_PROG(CSC, csc.exe, no)
+if test x$CSC = "xno"; then
 	AC_MSG_ERROR([You need to install either mono or .Net])
 else
 RUNTIME=
 fi
 fi
+
+CS="C#"
+if test "x$CSC" = "xno" ; then
+	AC_MSG_ERROR([No $CS compiler found])
+fi
+
 AC_SUBST(RUNTIME)
 AC_SUBST(CSC)
 
@@ -203,6 +209,7 @@ echo "---"
 echo "Configuration summary"
 echo ""
 echo "   * Installation prefix = $prefix"
+echo "   * $CS compiler: $CSC"
 echo ""
 echo "   Optional assemblies included in the build:"
 echo ""