Add `CMAKE_SYSROOT_COMPILE` and `CMAKE_SYSROOT_LINK` variables to as
operation-specific alternatives to `CMAKE_SYSROOT`. This will be useful
for Android NDKs that compile and link with different sysroot values
(e.g. `r14` with unified headers).
Co-Author: Florent Castelli <florent.castelli@gmail.com>
Refactoring in commit b29425f7 (cmLocalGenerator: Populate a container
of mappings for replacements, 2016-10-09) broke substitution of this
placeholder by storing the wrong key in the new replacement map.
Use the proper key, `CMAKE_<LANG>_COMPILER_ARG1`.
