[Static SDK] Turn off -Werror for BoringSSL.

`-Werror` is a stupid option; it basically breaks the build whenever
a newer compiler adds a new warning that triggers in your code.  We
don't need it here, so disable it.

Author: al45tair

swift-ci/sdks/static-linux/scripts/build.sh

@@ -239,6 +239,8 @@ function run() {
     "$@"
 }
 
+# -----------------------------------------------------------------------
+
 header "Building CMake from source"
 
 quiet_pushd ${source_dir}/swift-project/cmake
@@ -255,6 +257,8 @@ run export PATH="${build_dir}/cmake/install/bin:$PATH"
 quiet_popd
 run cmake --version
 
+# -----------------------------------------------------------------------
+
 header "Patching Musl"
 
 echo -n "Patching Musl for locale support... "
@@ -270,6 +274,14 @@ fi
 
 # -----------------------------------------------------------------------
 
+header "Patching BoringSSL"
+
+echo -n "Patching BoringSSL to disable -Werror... "
+sed -i.bak "s/-Werror //g" ${source_dir}/boringssl/CMakeLists.txt
+echo "done"
+
+# -----------------------------------------------------------------------
+
 header "Building clang for host"
 
 mkdir -p ${build_dir}/host/clang ${build_dir}/clang