Merge topic 'minor-cleanups'

84fac67 Don't allow include() of export(EXPORT) file at configure time.
faedd2b cmTarget: Fix system include annotation propagation.
9eb06d0 add_library: Disallow invalid signatures for INTERFACE_LIBRARY.
10d65d5 cmTarget: Move a variable initialization closer to where it is used.
0f3e8e9 Undefine local preprocessor loop variables.
9ba47ee Genex: Reform error-checking for nullary/unary expressions.
fa651c7 cmTarget: Remove some of the INTERFACE_LIBRARY whitelisted properties.
61d138a cmTarget: INTERFACE_LIBRARY is always EXCLUDE_FROM_ALL.
3429541 export: Rename some variables to reflect content type.
7461d67 cmTarget: Enable convenient include dir handling for INTERFACE_LIBRARY.
7fc6e3d cmTarget: Remove dead code.
2af966d Genex: Add EQUAL expression.
2d66380 cmTarget: Use strtol for numeric parsing.
Merge branch 'master' into next