SkiaSharp: Mac build does not work

Hi! I admittedly am new to Mac OS, but I setup a build environment for SkiaSharp and I get a quite meaningless exception when running sudo ./bootstrapper.sh -t externals-android

the relevant trace part is

[33/755] CC obj/third_party/externals/libwebp/src/dsp/libwebp_dsp.upsampling.o ninja: build stopped: subcommand failed. Executing: /Users/xammac/SkiaSharp/skia/platform_tools/android/bin/android_ninja -d arm_v7_neon skia_lib pdf sfntly icuuc GYP_GENERATORS is “ninja-android” Updating projects from gyp files… ninja: Entering directory /Users/xammac/SkiaSharp/skia/out/config/android-arm_v7_neon/Release' [349/1002] CXX obj/src/c/xamarin/core.sk_x_path.o FAILED: /Users/xammac/SkiaSharp/skia/platform_tools/android/bin/../toolchains/arm-r10e-14/bin/arm-linux-androideabi-g++ -MMD -MF obj/src/c/xamarin/core.sk_x_path.o.d -DSK_INTERNAL -DSK_GAMMA_APPLY_TO_A8 -DSK_ALLOW_STATIC_GLOBAL_INITIALIZERS=0 -DSK_SUPPORT_GPU=1 -DSK_FORCE_DISTANCE_FIELD_TEXT=0 -DSK_ARM_HAS_NEON -DSK_BUILD_FOR_ANDROID -DSK_GAMMA_EXPONENT=1.4 -DSK_GAMMA_CONTRAST=0.0 -DSKIA_DLL -DSKIA_IMPLEMENTATION=1 -DSK_SUPPORT_LEGACY_CLIPTOLAYERFLAG -DNDEBUG -I../../../../include/c -I../../../../include/config -I../../../../include/core -I../../../../include/pathops -I../../../../include/ports -I../../../../include/private -I../../../../include/utils -I../../../../include/images -I../../../../src/core -I../../../../src/sfnt -I../../../../src/image -I../../../../src/opts -I../../../../src/utils -I../../../../include/gpu -I../../../../src/gpu -I../../../../platform_tools/android/third_party/cpufeatures -fPIC -g -fno-exceptions -fstrict-aliasing -Wall -Wextra -Winit-self -Wpointer-arith -Wsign-compare -Wno-unused-parameter -Werror -march=armv7-a -mthumb -mfpu=neon -mfloat-abi=softfp -fuse-ld=gold -O2 -std=c++11 -fno-rtti -fno-threadsafe-statics -Wnon-virtual-dtor -c ../../../../src/c/xamarin/sk_x_path.cpp -o obj/src/c/xamarin/core.sk_x_path.o ../../../../src/c/xamarin/sk_x_path.cpp:94:38: error: comparison between 'enum SkPath::Verb' and 'enum sk_path_verb_t' [-Werror=enum-compare] static_assert (SkPath::kMove_Verb == MOVE_PATH_VERB, "ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:95:38: error: comparison between 'enum SkPath::Verb' and 'enum sk_path_verb_t' [-Werror=enum-compare] static_assert (SkPath::kLine_Verb == LINE_PATH_VERB, "ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:96:38: error: comparison between 'enum SkPath::Verb' and 'enum sk_path_verb_t' [-Werror=enum-compare] static_assert (SkPath::kQuad_Verb == QUAD_PATH_VERB, "ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:97:39: error: comparison between 'enum SkPath::Verb' and 'enum sk_path_verb_t' [-Werror=enum-compare] static_assert (SkPath::kConic_Verb == CONIC_PATH_VERB, "ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:98:39: error: comparison between 'enum SkPath::Verb' and 'enum sk_path_verb_t' [-Werror=enum-compare] static_assert (SkPath::kCubic_Verb == CUBIC_PATH_VERB, "ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:99:39: error: comparison between 'enum SkPath::Verb' and 'enum sk_path_verb_t' [-Werror=enum-compare] static_assert (SkPath::kClose_Verb == CLOSE_PATH_VERB, "ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:100:38: error: comparison between 'enum SkPath::Verb' and 'enum sk_path_verb_t' [-Werror=enum-compare] static_assert (SkPath::kDone_Verb == DONE_PATH_VERB, "ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:127:47: error: comparison between 'enum SkPath::AddPathMode' and 'enum sk_path_add_mode_t' [-Werror=enum-compare] static_assert (SkPath::kAppend_AddPathMode == APPEND_ADD_MODE, "ABI changed, you must write a enumeration mapper for SkPath::AddPathMode to sk_path_add_mode_t"); ^ ../../../../src/c/xamarin/sk_x_path.cpp:128:47: error: comparison between 'enum SkPath::AddPathMode' and 'enum sk_path_add_mode_t' [-Werror=enum-compare] static_assert (SkPath::kExtend_AddPathMode == EXTEND_ADD_MODE, "ABI changed, you must write a enumeration mapper for SkPath::AddPathMode to sk_path_add_mode_t"); ^ cc1plus: all warnings being treated as errors [349/1002] CXX obj/third_party/externals/sfntly/sfntly/table/truetype/sfntly.glyph_table.o ninja: build stopped: subcommand failed. Executing: /Users/xammac/SkiaSharp/skia/platform_tools/android/bin/android_ninja -d arm64 skia_lib pdf sfntly icuuc GYP_GENERATORS is "ninja-android" Updating projects from gyp files... ninja: Entering directory/Users/xammac/SkiaSharp/skia/out/config/android-arm64/Release’ [20/647] CXX obj/src/c/xamarin/core.sk_x_path.o FAILED: /Users/xammac/SkiaSharp/skia/platform_tools/android/bin/…/toolchains/arm64-r10e-21/bin/aarch64-linux-android-g++ -MMD -MF obj/src/c/xamarin/core.sk_x_path.o.d -DSK_INTERNAL -DSK_GAMMA_APPLY_TO_A8 -DSK_ALLOW_STATIC_GLOBAL_INITIALIZERS=0 -DSK_SUPPORT_GPU=1 -DSK_FORCE_DISTANCE_FIELD_TEXT=0 -DSK_BUILD_FOR_ANDROID -DSK_GAMMA_EXPONENT=1.4 -DSK_GAMMA_CONTRAST=0.0 -DSKIA_DLL -DSKIA_IMPLEMENTATION=1 -DSK_SUPPORT_LEGACY_CLIPTOLAYERFLAG -DNDEBUG -I…/…/…/…/include/c -I…/…/…/…/include/config -I…/…/…/…/include/core -I…/…/…/…/include/pathops -I…/…/…/…/include/ports -I…/…/…/…/include/private -I…/…/…/…/include/utils -I…/…/…/…/include/images -I…/…/…/…/src/core -I…/…/…/…/src/sfnt -I…/…/…/…/src/image -I…/…/…/…/src/opts -I…/…/…/…/src/utils -I…/…/…/…/include/gpu -I…/…/…/…/src/gpu -I…/…/…/…/platform_tools/android/third_party/cpufeatures -fPIC -g -fno-exceptions -fstrict-aliasing -Wall -Wextra -Winit-self -Wpointer-arith -Wsign-compare -Wno-unused-parameter -Werror -fuse-ld=gold -O2 -std=c++11 -fno-rtti -fno-threadsafe-statics -Wnon-virtual-dtor -c …/…/…/…/src/c/xamarin/sk_x_path.cpp -o obj/src/c/xamarin/core.sk_x_path.o …/…/…/…/src/c/xamarin/sk_x_path.cpp:94:38: error: comparison between ‘enum SkPath::Verb’ and ‘enum sk_path_verb_t’ [-Werror=enum-compare] static_assert (SkPath::kMove_Verb == MOVE_PATH_VERB, “ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp:95:38: error: comparison between ‘enum SkPath::Verb’ and ‘enum sk_path_verb_t’ [-Werror=enum-compare] static_assert (SkPath::kLine_Verb == LINE_PATH_VERB, “ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp:96:38: error: comparison between ‘enum SkPath::Verb’ and ‘enum sk_path_verb_t’ [-Werror=enum-compare] static_assert (SkPath::kQuad_Verb == QUAD_PATH_VERB, “ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp:97:39: error: comparison between ‘enum SkPath::Verb’ and ‘enum sk_path_verb_t’ [-Werror=enum-compare] static_assert (SkPath::kConic_Verb == CONIC_PATH_VERB, “ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp:98:39: error: comparison between ‘enum SkPath::Verb’ and ‘enum sk_path_verb_t’ [-Werror=enum-compare] static_assert (SkPath::kCubic_Verb == CUBIC_PATH_VERB, “ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp:99:39: error: comparison between ‘enum SkPath::Verb’ and ‘enum sk_path_verb_t’ [-Werror=enum-compare] static_assert (SkPath::kClose_Verb == CLOSE_PATH_VERB, “ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp💯38: error: comparison between ‘enum SkPath::Verb’ and ‘enum sk_path_verb_t’ [-Werror=enum-compare] static_assert (SkPath::kDone_Verb == DONE_PATH_VERB, “ABI changed, you must write a enumeration mapper for SkPath::Verb to sk_path_verb_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp:127:47: error: comparison between ‘enum SkPath::AddPathMode’ and ‘enum sk_path_add_mode_t’ [-Werror=enum-compare] static_assert (SkPath::kAppend_AddPathMode == APPEND_ADD_MODE, “ABI changed, you must write a enumeration mapper for SkPath::AddPathMode to sk_path_add_mode_t”); ^ …/…/…/…/src/c/xamarin/sk_x_path.cpp:128:47: error: comparison between ‘enum SkPath::AddPathMode’ and ‘enum sk_path_add_mode_t’ [-Werror=enum-compare] static_assert (SkPath::kExtend_AddPathMode == EXTEND_ADD_MODE, “ABI changed, you must write a enumeration mapper for SkPath::AddPathMode to sk_path_add_mode_t”); ^ cc1plus: all warnings being treated as errors [20/647] CXX obj/src/core/core.SkAAClip.o ninja: build stopped: subcommand failed. Executing: /Users/xammac/Library/Developer/Xamarin/android-ndk/ndk-build An error occured when executing task ‘externals-android’. Error: System.ComponentModel.Win32Exception: ApplicationName=‘/Users/xammac/Library/Developer/Xamarin/android-ndk/ndk-build’, CommandLine=‘’, CurrentDirectory=‘/Users/xammac/SkiaSharp/native-builds/libSkiaSharp_android’, Native error= Cannot find the specified file at System.Diagnostics.Process.Start_noshell (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process) <0x39cf1e8 + 0x0055f> in <filename unknown>:0

any advice would be greatly appreciated