See https://bugs.openjdk.org/browse/JDK-8288719 and discussion https://mail.openjdk.org/pipermail/build-dev/2022-May/034635.html.

On Arm, we can generate either arm- or thumb-code (-marm or -mthumb). At the moment, if we don't specify an ABI profile when configuring the build, we call gcc without explicitly specifying `-marm` or `-mthumb`. Then we use whatever the toolchains defaults too, which is pretty much random (it depends on how the toolchain itself had been built). That can cause really rare but tricky problems when combining static assembly and C++ code. For an example, see JDK-8288719.

I propose to always specify -marm to prevent such errors, unless one specified an explicit flag