Fix RPI CI build failure

Update missing toolchain systempath to include python files correctly.
This regression happens by PR #38399.

Also skip OpenBLAS build for RPI 2/3 to improve build speed.

PiperOrigin-RevId: 308721738
Change-Id: I42a1ff1b104190ba3de7644f1af8d12997b7dd1e

tensorflow/tools/ci_build/pi/build_raspberry_pi.sh

@@ -50,6 +50,7 @@ fi
 
 WORKSPACE_PATH=`pwd`
 
+if [[ $1 == "PI_ONE" ]]; then
   # Build the OpenBLAS library, which is faster than Eigen on the Pi Zero/One.
   # TODO(petewarden) - It would be nicer to move this into the main Bazel build
   # process if we can maintain a build file for this.
@@ -77,7 +78,6 @@ OPENBLAS_INSTALL_PATH=/tmp/openblas_install/
   make CC=${CROSSTOOL_CC} FC=${CROSSTOOL_CC} HOSTCC=gcc TARGET=ARMV6
   make PREFIX=${OPENBLAS_INSTALL_PATH} install
 
-if [[ $1 == "PI_ONE" ]]; then
   PI_COPTS="--copt=-march=armv6 --copt=-mfpu=vfp
   --copt=-DUSE_GEMM_FOR_CONV --copt=-DUSE_OPENBLAS
   --copt=-isystem --copt=${OPENBLAS_INSTALL_PATH}/include/

third_party/toolchains/cpus/arm/cc_config.bzl.tpl

@@ -351,11 +351,13 @@ def _impl(ctx):
                                 "-isystem",
                                 "%{ARM_COMPILER_PATH}%/lib/gcc/arm-rpi-linux-gnueabihf/6.5.0/include-fixed",
                                 "-isystem",
-                                "%{ARM_COMPILER_PATH}%/arm-rpi-linux-gnueabihf/sysroot/usr/include/",
-                                "-isystem",
                                 "%{ARM_COMPILER_PATH}%/arm-rpi-linux-gnueabihf/include/c++/6.5.0/",
                                 "-isystem",
+                                "%{ARM_COMPILER_PATH}%/arm-rpi-linux-gnueabihf/sysroot/usr/include/",
+                                "-isystem",
                                 "%{PYTHON_INCLUDE_PATH}%",
+                                "-isystem",
+                                "/usr/include/",
                             ],
                         ),
                     ],