GCC Toolchain Path Incorrect Post R22 NDK

[GEMISIS]

After R22 of the NDK, the NDK is clang only for build it seems? Per android/ndk#1375 this means that the GCC toolchains that are attempting to be found no longer are (specifically at

buck/src/com/facebook/buck/android/toolchain/ndk/impl/NdkCxxPlatforms.java

Lines 1250 to 1253 in 5444652

	Path getNdkGccToolRoot() {
	return processDirectoryPathPattern(
	"toolchains/{toolchain}-{gcc_compiler_version}/prebuilt/{hostname}");
	}

this causes error using newer toolchains than R22).

[GEMISIS]

Looks like my original bug was an issue with my paths, but there is still an issue in that GCC related tools are being linked in the toolchain, which are no longer included with the NDK after R22.

[GEMISIS]

Actually, looks at this again, it may also be that it's failing before getting to what my original comment was discussing?

Per android/ndk#1407, the sysroot path for NDK is now contained in /toolchains/llvm/prebuilt//sysroot instead of the top level directory. This means that buck is looking in the wrong spot for the sysroot directory at

buck/src/com/facebook/buck/android/toolchain/ndk/impl/NdkCxxPlatforms.java

Line 1209 in 5444652

return processDirectoryPathPattern("sysroot");

It seems that NDK support may not have been kept up to date?

[GEMISIS]

Yeah, it looks like in the NdkCxxPlatforms.java file, there's a lot of updates that need to happen for more recent versions of the NDK, as everything after R19 is completely broken. The latest I've managed to get building on Windows is NDK version 19.2.5345600.

[LegNeato]

#2685