Broken cmake caching

[dimatcimbal]

Apparently libgit2 repo contains conflicting installs in src/libgit2/CMakeLists.txt.

The first line https://github.com/libgit2/libgit2/blob/main/src/libgit2/CMakeLists.txt#L135 installs a placeholder file ${PROJECT_SOURCE_DIR}/include/git2/experimental.h and then second https://github.com/libgit2/libgit2/blob/main/src/libgit2/CMakeLists.txt#L137 overrides it with the generated version ${PROJECT_BINARY_DIR}/include/git2/experimental.h.

# src/libgit2/CMakeLists.txt
L135: install(DIRECTORY ${PROJECT_SOURCE_DIR}/include/git2/
L136:        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${LIBGIT2_FILENAME}")
L137: install(FILES ${PROJECT_BINARY_DIR}/include/git2/experimental.h
L138:        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${LIBGIT2_FILENAME}")

This nullifies cmake cache (please find repeated Installing lines below) and forces a rebuild of dependent projects.

-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2/refs.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2/reset.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2/filter.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2/transaction.h
-- Installing: /Users/dimatcimbal/code/libgit2/installdir/include/git2/experimental.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2/stdint.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2/commit.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2/refdb.h
-- Installing: /Users/dimatcimbal/code/libgit2/installdir/include/git2/experimental.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/include/git2.h
-- Up-to-date: /Users/dimatcimbal/code/libgit2/installdir/bin/git2

The fix: #7109