Updated libunwind, libcxx and libcxx patches and build commands

Build libcxx and libcxxabi (succeeding) and libunwind (patch rebased
but build not working).

patches/libcxxabi-0001.patch

@@ -0,0 +1,25 @@
+From af6e844261dda2786985ff43fcd6873b636b57aa Mon Sep 17 00:00:00 2001
+From: Martin Storsjo <martin@martin.st>
+Date: Sat, 27 Aug 2016 14:02:18 +0300
+Subject: [PATCH] Hack cmake configure
+
+---
+ CMakeLists.txt | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 300d6da..d00a942 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -47,7 +47,7 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+     set(LLVM_INCLUDE_DIR ${INCLUDE_DIR} CACHE PATH "Path to llvm/include")
+     set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
+     set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
+-    set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/share/llvm/cmake")
++    set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/lib/cmake/llvm")
+     set(LLVM_LIT_PATH "${LLVM_PATH}/utils/lit/lit.py")
+   else()
+     message(FATAL_ERROR "llvm-config not found and LLVM_MAIN_SRC_DIR not defined. "
+-- 
+2.7.4
+