From 0b7bc77e305d8d4bd5615e54cf61f32cd0cac9c2 Mon Sep 17 00:00:00 2001
From: Oscar Fuentes <ofv@wanadoo.es>
Date: Sat, 2 Apr 2011 13:21:12 +0000
Subject: [PATCH] Handle changing of LLVM_ENABLE_FFI.

If someone first configure build with LLVM_ENABLE_FFI=1 and then turn it
off, the build will fail in lib/ExecutionEngine/Interpreter because
Interpreter will try still to #include <ffi/ffi.h>, but there are no
include_directories(${FFI_INCLUDE_DIR}) now.

This patch unset()'s HAVE_FFI_H and HAVE_FFI_FFI_H from cache file if
LLVM_ENABLE_FFI=0. This forces CMake to update config.h.

Patch by arrowdodger!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128769 91177308-0d34-0410-b5e6-96231b3b80d8
---
 cmake/config-ix.cmake | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index c5ec54eb0c6..e446853ef75 100755
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -271,6 +271,10 @@ if( LLVM_ENABLE_FFI )
   check_symbol_exists(ffi_call ${FFI_HEADER} HAVE_FFI_CALL)
   list(REMOVE_ITEM CMAKE_REQUIRED_INCLUDES ${FFI_INCLUDE_PATH})
   list(REMOVE_ITEM CMAKE_REQUIRED_LIBRARIES ${FFI_LIBRARY_PATH})
+else()
+  unset(HAVE_FFI_FFI_H CACHE)
+  unset(HAVE_FFI_H CACHE)
+  unset(HAVE_FFI_CALL CACHE)
 endif( LLVM_ENABLE_FFI )
 
 # Define LLVM_MULTITHREADED if gcc atomic builtins exists.