Updates to Tests/Fortran by commit v3.2.0-rc1~501^2 (Avoid if() quoted
auto-dereference, 2014-10-14) changed our check
"${CMAKE_Fortran_COMPILER_ID}" MATCHES "${CMAKE_C_COMPILER_ID}"
to
CMAKE_Fortran_COMPILER_ID MATCHES CMAKE_C_COMPILER_ID
because CMP0054 warned about the LHS compiler id "MSVC" being expanded.
However, the RHS of if(MATCHES) does not auto-dereference so this check
has returned FALSE since then and the FortranCInterface part of the test
has not been running!
Fix this by using STREQUAL with quoted arguments and setting CMP0054 to
NEW (by requiring 3.1).
d31d7ffd1e