configure: Check for gdc for D compiler
diff --git a/configure.ac b/configure.ac
index 050d975..a63a76a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -705,7 +705,7 @@
   fi
 
   if test -z "$D2COMPILERBIN" ; then
-    AC_CHECK_PROGS(D2COMPILER, dmd gdmd ldmd2 ldc2)
+    AC_CHECK_PROGS(D2COMPILER, dmd gdmd ldmd2 ldc2 gdc)
 
     if test -n "$D2COMPILER" ; then
       AC_MSG_CHECKING(whether the D2 compiler works)