Deprecate Autoconf

As per the very positive feedback from llvm-dev (http://lists.llvm.org/pipermail/llvm-dev/2015-November/092150.html), this commit officially deprecates the LLVM autoconf-based build system.

Anyone still using it should switch to CMake.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252520 91177308-0d34-0410-b5e6-96231b3b80d8

configure

@@ -19379,3 +19379,15 @@ echo "$as_me: error: $ac_sub_configure failed for $ac_dir" >&2;}
   done
 fi
 
+echo ""
+echo ""
+echo "################################################################################"
+echo "################################################################################"
+echo "The LLVM project has deprecated building with configure & make."
+echo "The autoconf-based makefile build system will be removed in the 3.9 release."
+echo ""
+echo "Please migrate to the CMake-based build system."
+echo "For more information see: http://llvm.org/docs/CMake.html"
+echo "################################################################################"
+echo "################################################################################"
+

docs/BuildingLLVMWithAutotools.rst

@@ -5,6 +5,12 @@ Building LLVM With Autotools
 .. contents::
    :local:
 
+.. warning::
+
+    Building LLVM with autoconf is deprecated as of 3.8. The autoconf build
+    system will be removed in 3.9. Please migrate to using CMake. For more
+    information see: `Building LLVM with CMake <CMake.html>`_
+
 Overview
 ========
 

docs/ReleaseNotes.rst

@@ -37,6 +37,10 @@ Non-comprehensive list of changes in this release
   Windows 7. Earlier versions, including Windows Vista and XP are no longer
   supported.
 
+* With this release, the autoconf build system is deprecated. It will be removed
+  in the 3.9 release. Please migrate to using CMake. For more information see:
+  `Building LLVM with CMake <CMake.html>`_
+
 .. NOTE
    For small 1-3 sentence descriptions, just add an entry at the end of
    this list. If your description won't fit comfortably in one bullet