experiment: build grpc_csharp_ext for ios

src/csharp/experimental/build_native_ext_for_ios.sh

@@ -0,0 +1,45 @@
+#!/bin/sh
+# Copyright 2018 The gRPC Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Helper script to crosscompile grpc_csharp_ext native extension for Android.
+
+set -ex
+
+cd "$(dirname "$0")/../../.."
+
+# <iphoneos|iphonesimulator>
+SDK="iphoneos"
+# <arm64|x86_64|...>
+ARCH="arm64"
+
+PATH_AR="$(xcrun --sdk $SDK --find ar)"
+PATH_CC="$(xcrun --sdk $SDK --find clang)"
+PATH_CXX="$(xcrun --sdk $SDK --find clang++)"
+
+# TODO(jtattermusch): add  -mios-version-min=6.0 and -Wl,ios_version_min=6.0
+CPPFLAGS="-O2 -Wframe-larger-than=16384 -arch $ARCH -isysroot $(xcrun --sdk $SDK --show-sdk-path) -DPB_NO_PACKED_STRUCTS=1"
+LDFLAGS="-arch $ARCH -isysroot $(xcrun --sdk $SDK --show-sdk-path)"
+
+# TODO(jtattermusch): revisit the build arguments
+make -j4 static_csharp \
+    VALID_CONFIG_ios_$ARCH="1" \
+    CC_ios_$ARCH="$PATH_CC" \
+    CXX_ios_$ARCH="$PATH_CXX" \
+    LD_ios_$ARCH="$PATH_CC" \
+    LDXX_ios_$ARCH="$PATH_CXX" \
+    CPPFLAGS_ios_$ARCH="$CPPFLAGS" \
+    LDFLAGS_ios_$ARCH="$LDFLAGS" \
+    DEFINES_ios_$ARCH="NDEBUG" \
+    CONFIG="ios_$ARCH"