[POWERPC] Add PowerPC Cross Compile Toolchain

Toolchain to cross compile to PowerPC.

Change-Id: I4d31a204fe2d6c948f1d526fc93c6c5206061c94
diff --git a/build/cmake/toolchains/ppc-linux-gcc.cmake b/build/cmake/toolchains/ppc-linux-gcc.cmake
new file mode 100644
index 0000000..c7a0364
--- /dev/null
+++ b/build/cmake/toolchains/ppc-linux-gcc.cmake
@@ -0,0 +1,28 @@
+##
+## Copyright (c) 2018, Alliance for Open Media. All rights reserved
+##
+## This source code is subject to the terms of the BSD 2 Clause License and
+## the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+## was not distributed with this source code in the LICENSE file, you can
+## obtain it at www.aomedia.org/license/software. If the Alliance for Open
+## Media Patent License 1.0 was not distributed with this source code in the
+## PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+##
+if (NOT AOM_BUILD_CMAKE_TOOLCHAINS_PPC_LINUX_GCC_CMAKE_)
+set(AOM_BUILD_CMAKE_TOOLCHAINS_PPC_LINUX_GCC_CMAKE_ 1)
+
+set(CMAKE_SYSTEM_NAME "Linux")
+
+if ("${CROSS}" STREQUAL "")
+  # Default the cross compiler prefix to something known to work.
+  set(CROSS powerpc64le-linux-gnu-)
+endif ()
+
+set(CMAKE_C_COMPILER ${CROSS}gcc)
+set(CMAKE_CXX_COMPILER ${CROSS}g++)
+set(AS_EXECUTABLE ${CROSS}as)
+set(CMAKE_SYSTEM_PROCESSOR "ppc")
+
+set(CONFIG_RUNTIME_CPU_DETECT 0 CACHE NUMBER "")
+
+endif ()  # AOM_BUILD_CMAKE_TOOLCHAINS_PPC_LINUX_GCC_CMAKE_