Fix boostrapping on less optimizing compilers

While compilers are allowed to drop unused functions in anonymous
name spaces, and in this way also the open linker symbols referenced
there, they are not obliged to do so. Not optimizing away such
unused functions when compiled with -DBOOTSTRAP_BUILD_TOOL causes
the linking fail in the initial phase of the boostrap process where
libgit2 is not yet available (nor really needed). Therefore, ensure
that those dead functions are absent in the initial bootstrap phase
using appropriate preprocessor directives.

Signed-off-by: Klaus T. Aehlig <aehlig@linta.de>

1 files changed, 2 insertions, 8 deletions

diff --git a/src/buildtool/file_system/git_repo.cpp b/src/buildtool/file_system/git_repo.cpp
index e7db261a..0aba51a2 100644
--- a/src/buildtool/file_system/git_repo.cpp
+++ b/src/buildtool/file_system/git_repo.cpp
@@ -23,6 +23,7 @@ extern "C" {
 #include <git2/sys/odb_backend.h>
 }
 
+#ifndef BOOTSTRAP_BUILD_TOOL
 namespace {
 
 constexpr std::size_t kWaitTime{2};  // time in ms between tries for git locks
@@ -273,13 +274,9 @@ void backend_free(git_odb_backend* /*_backend*/) {}
     return b;
 }
 
-#ifndef BOOTSTRAP_BUILD_TOOL
-
 // A backend that can be used to read and create tree objects in-memory.
 auto const kInMemoryODBParent = CreateInMemoryODBParent();
 
-#endif  // BOOTSTRAP_BUILD_TOOL
-
 struct FetchIntoODBBackend {
     git_odb_backend parent;
     git_odb* target_odb;  // the odb where the fetch objects will end up into
@@ -319,13 +316,9 @@ void fetch_backend_free(git_odb_backend* /*_backend*/) {}
     return b;
 }
 
-#ifndef BOOTSTRAP_BUILD_TOOL
-
 // A backend that can be used to fetch from the remote of another repository.
 auto const kFetchIntoODBParent = CreateFetchIntoODBParent();
 
-#endif  // BOOTSTRAP_BUILD_TOOL
-
 // callback to enable SSL certificate check for remote fetch
 const auto certificate_check_cb = [](git_cert* /*cert*/,
                                      int /*valid*/,
@@ -369,6 +362,7 @@ const auto certificate_passthrough_cb = [](git_cert* /*cert*/,
 }
 
 }  // namespace
+#endif  // BOOTSTRAP_BUILD_TOOL
 
 auto GitRepo::Open(GitCASPtr git_cas) noexcept -> std::optional<GitRepo> {
 #ifdef BOOTSTRAP_BUILD_TOOL