Removing the Makefile+Perl build system

[jlpeyton]

Summary

This change deletes the Makefile+Perl build system and all files used by it which aren't used by the CMake build system. This included many Perl files, *.mk files, iomp* files.
This change also updates the README's and index.html to instruct the user to use the CMake build system. All mentioning of the Perl+Makefile based system are removed.

[jmellorcrummey]

LGTM.

[jcownie]

The LLVM OpenMP landing page contains instructions on getting started that tell people to use the Makefile. Therefore that also needs to be updated to reflect this change.

[jlpeyton]

Updated the diff to address the website instructions. I took a lot of the text from libcxx since it is a similar build process.

[jlpeyton]

Changing this diff to remove all the Makefile+Perl files.

[jlpeyton]

Updating the READMEs to include instructions for basic In-tree and out-of-tree documentation. They mimic the index.html file's instructions.

[Hahnfeld]

Please see inline comments

runtime/README.txt

114

the build dir may not necessarily be inside the src dir. libc++ uses path/to/libcxx...

www/index.html

158 ↗

(On Diff #33598)

Do we really want to call it libomp?

I remember D9534 where it was expected to be called openmp. And there may be other components than just libomp in this repository at some point of time...

(Please also fix the other locations where it says libomp)

[jlpeyton]

the build dir may not necessarily be inside the src dir. libc++ uses path/to/libcxx...

I had the source and build directories mixed up in my head and didn't think this would work. I was wrong.
Changed.

Do we really want to call it libomp?
I remember D9534 where it was expected to be called openmp. And there may be other components than just libomp in this repository at some point of time...
(Please also fix the other locations where it says libomp)

Changed.

[Hahnfeld]

LGTM

runtime/Makefile

 #
 #//===----------------------------------------------------------------------===//
 #//
 #//                     The LLVM Compiler Infrastructure
 #//
 #// This file is dual licensed under the MIT and the University of Illinois Open
 #// Source Licenses. See LICENSE.txt for details.
 #//
 #//===----------------------------------------------------------------------===//
 #
 
 omp_root?=.
 include $(omp_root)/tools/common.inc
 .PHONY: default all omp
 
-default: omp
+default:
+  @echo --- This Makefile system is deprecated and is not being updated anymore.
+  @echo --- It will be deleted in the future.
+  @echo --- To build libomp, please use the CMake build system
+  @echo --- which is documented in Build_With_CMake.txt
 
 all: omp stubs
 
 omp: info mkdir
   @echo $(omp_root)/tools/build.pl $(build_args) --arch=$(arch) --mode=$(mode) lib inc common -- -j$(jobs)
   $(omp_root)/tools/build.pl $(build_args) --arch=$(arch) --mode=$(mode) lib inc common -- -j$(jobs)
 
 stubs: mkdir

runtime/README.txt

 architectures, and for those already familiar with Cmake that may be
 an easier route to take than the one described here.
 
 Building with CMake
 ===================
 The runtime/Build_With_CMake.txt file has a description of how to
 build with Cmake.
 
-Building with the Makefile
+Building with the Makefile (deprecated)
 ==========================
+*** This build system is no longer being updated and should not be used
+*** to build libomp.  Please use the CMake build system.
+
 The Makefile at the top-level will attempt to detect what it needs to
 build the LLVM* OpenMP* Runtime Library.  To see the default settings, 
 type:
 
 make info
 
 You can change the Makefile's behavior with the following options:
 
Intel(R) Many Integrated Core Architecture
 
               ----------------------------------------------
               |   icc/icl     |    gcc      |   clang      |
 --------------|---------------|----------------------------|
 | Linux* OS   |   Yes(1,5)    |  Yes(2,4)   | Yes(4,6,7)   |
 | FreeBSD*    |   No          |  No         | Yes(4,6,7,8) |
 | OS X*       |   Yes(1,3,4)  |  No         | Yes(4,6,7)   |
 | Windows* OS |   Yes(1,4)    |  No         | No           |
 ------------------------------------------------------------
 
 (1) On IA-32 architecture and Intel(R) 64, icc/icl versions 12.x are 
     supported (12.1 is recommended).
 (2) GCC* version 4.6.2 is supported.
 (3) For icc on OS X*, OS X* version 10.5.8 is supported.
 (4) Intel(R) Many Integrated Core Architecture not supported.
 (5) On Intel(R) Many Integrated Core Architecture, icc/icl versions 13.0 
     or later are required.

www/README.txt

 architectures, and for those already familiar with Cmake that may be
 an easier route to take than the one described here.
 
 Building with CMake
 ===================
 The runtime/Build_With_CMake.txt file has a description of how to
 build with Cmake.
 
-Building with the Makefile
+Building with the Makefile (deprecated)
 ==========================
+*** This build system is no longer being updated and should not be used
+*** to build libomp.  Please use the CMake build system.
+
 The Makefile at the top-level will attempt to detect what it needs to
 build the LLVM* OpenMP* Runtime Library.  To see the default settings, 
 type:
 
 make info
 
 You can change the Makefile's behavior with the following options: