Fix build breakage introduced by #1911

[lakshmih]

1911 is breaking the Android build for us, so would appreciate if this fix or an equivalent one could be reviewed and merged.

[svenvh]

@okias since you authored #1911: does this proposed fix still work with your use case?

[okias]

@svenvh still working properly for musl-libc, thanks for the ping!

[bashbaug]

Merging as discussed in the May 7th teleconference.

Two areas for follow-up:

• Can we do this check in CMake, to choose the right version of strerror_r?
• Why wasn't this break found in CI?