libgit2-glib @0.23.6 does not build on 10.6.8

[udbraumann]

While updating libgit2-glib from @0.23.4 to @0.23.6 I run into this problem:

...
:info:build libtool: compile:  /usr/bin/llvm-gcc-4.2 -arch x86_64 -DHAVE_CONFIG_H -I. -I.. -I.. -I.. -I. -D_REENTRANT -I/opt/local/include -I/opt/local/include/gobject-introspection-1.0 -I/opt/local/lib/libffi-3.2.1/include -I/opt/local/i
nclude/glib-2.0 -I/opt/local/lib/glib-2.0/include -I/opt/local/include -I/opt/local/include -DGIT_SSH=1 -Wall -I/opt/local/include -pipe -Os -arch x86_64 -MT ggit-branch-enumerator.lo -MD -MP -MF .deps/ggit-branch-enumerator.Tpo -c ggit-b
ranch-enumerator.c  -fno-common -DPIC -o .libs/ggit-branch-enumerator.o
:info:build In file included from ggit-branch.h:24,
:info:build                  from ggit-branch.c:21:
:info:build ../libgit2-glib/ggit-ref.h:33: error: redefinition of typedef ‘GgitRef’
:info:build ../libgit2-glib/ggit-types.h:201: error: previous declaration of ‘GgitRef’ was here
:info:build make[3]: *** [ggit-branch.lo] Error 1
:info:build make[3]: *** Waiting for unfinished jobs....
:info:build In file included from ../libgit2-glib/ggit-branch.h:24,
:info:build                  from ggit-branch-enumerator.h:28,
:info:build                  from ggit-branch-enumerator.c:1:
:info:build ../libgit2-glib/ggit-ref.h:33: error: redefinition of typedef ‘GgitRef’
:info:build ../libgit2-glib/ggit-types.h:201: error: previous declaration of ‘GgitRef’ was here
:info:build make[3]: *** [ggit-branch-enumerator.lo] Error 1
:info:build mv -f .deps/ggit-blob.Tpo .deps/ggit-blob.Plo
:info:build mv -f .deps/ggit-blame-options.Tpo .deps/ggit-blame-options.Plo
:info:build mv -f .deps/ggit-enum-types.Tpo .deps/ggit-enum-types.Plo
:info:build mv -f .deps/ggit-blame.Tpo .deps/ggit-blame.Plo
:info:build mv -f .deps/ggit-annotated-commit.Tpo .deps/ggit-annotated-commit.Plo
:info:build In file included from ../libgit2-glib/ggit-branch.h:24,
:info:build                  from ggit-repository.h:34,
:info:build                  from ggit-blob-output-stream.c:22:
:info:build ../libgit2-glib/ggit-ref.h:33: error: redefinition of typedef ‘GgitRef’
:info:build ggit-types.h:201: error: previous declaration of ‘GgitRef’ was here
:info:build In file included from ggit-repository.h:40,
:info:build                  from ggit-blob-output-stream.c:22:
:info:build ../libgit2-glib/ggit-commit.h:37: error: redefinition of typedef ‘GgitCommit’
:info:build ../libgit2-glib/ggit-commit-parents.h:31: error: previous declaration of ‘GgitCommit’ was here
:info:build In file included from ggit-repository.h:42,
:info:build                  from ggit-blob-output-stream.c:22:
:info:build ../libgit2-glib/ggit-remote.h:34: error: redefinition of typedef ‘GgitRemote’
:info:build ggit-types.h:236: error: previous declaration of ‘GgitRemote’ was here
:info:build make[3]: *** [ggit-blob-output-stream.lo] Error 1
...

Will a more modern compiler tolerate this typedef redefinition?

[udbraumann]

macports-gcc-5 was able to build libgit2-glib @0.23.6.

[dbevans (David B. Evans)]

Replying to braumann@…:

Will a more modern compiler tolerate this typedef redefinition?

Yes. Traditionally C has not allowed typedef redefinition but C++ has. Typedef redefinition in C is now allowed as of the C11 standard. So you need a compiler that understands/accepts C11 code. In particular, gcc-4.2 and llvm-gcc-4.2 are outdated and do not. Newer clang and gcc compilers do.

[dbevans (David B. Evans)]

Fix committed in r142884 which blacklists default 10.6 compilers. Builds correctly on SL buildbot. Thanks for your report.