IPO: involve gcc-ar and gcc-ranlib in LTO test as well
IPO: output IPO specific variables to determine if IPO is in use
Merge topic 'gcc-ipo' into next

74c3875b IPO: output IPO specific variables to determine if IPO is in use
cafc60ef IPO: involve gcc-ar and gcc-ranlib in LTO test as well
add_library: Test invalid GLOBAL INTERFACE signature.

This has to be tested separately from the invalid_signature test because
target sources are evaluate at a later time, and earlier errors in the
invalid_signature test cause early exit.
add_library: Issue better diagnostic for INTERFACE GLOBAL signature.
Merge topic 'interface-library-signatures' into next

6d85a6a6 add_library: Issue better diagnostic for INTERFACE GLOBAL signature.
770245e9 add_library: Test invalid GLOBAL INTERFACE signature.