Summary:
This fixes PR34547.
`Lexer::LexEndOfFile` handles recording of ConditionalStack for
preamble and reporting errors about unmatched conditionalal PP
directives.
However, SkipExcludedConditionalBlock contianed duplicated logic for
reporting errors and clearing ConditionalStack, but not for preamble
recording.
This fix removes error reporting logic from
`SkipExcludedConditionalBlock`, unmatched PP conditionals are now
reported inside `Lexer::LexEndOfFile`.
Reviewers: erikjv, klimek, bkramer
Reviewed By: erikjv
Subscribers: nik, cfe-commits
Differential Revision: https://reviews.llvm.org/D37700
llvm-svn: 313014