Recognize Interix systems as if they were SunOS and make sure we don't
attempt to configure for "Unknown" system types.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16120 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 55c4d7e..94b306f 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -128,6 +128,10 @@
              AC_SUBST(OS,[AIX])
              platform_type="AIX"
              ;;
+        *-*-interix*)
+             AC_SUBST(OS,[SunOS])
+             platform_type="SunOS"
+             ;;
         *-*-win32*)
              AC_SUBST(OS,[Win32])
              platform_type="Win32"
@@ -138,6 +142,11 @@
 	     ;;
 esac
 
+dnl Make sure we aren't attempting to configure for an unknown system
+if test $platform_type -eq "Unknown" ; then
+  AC_MSG_ERROR([Platform is unknown, configure can't continue])
+fi
+
 dnl Make a link from lib/System/platform to lib/System/$platform_type
 dnl This helps the #inclusion of the system specific include files
 dnl for the operating system abstraction library