Also disable this if NO_SAFE_LIBINSTALL is defined.
There is little harm in always using -S and it fixes several issues:
- A race during 'make libraries' where, for example, libgcc_s is being
installed while another library is trying to link against it. This is
possible because libgcc_s is connected in both _prereq_libs and
_startup_libs. The first build (_prereq_libs) sets MK_PROFILE=no
while the 2nd pass (_startup_libs) enables MK_PROFILE. Thus the
libgcc_s library *is* present in WORLDTMP for other libraries to
link to, so serializing further items in _startup_libs is not
required. Just ensuring that libgcc_s is installed atomically (via
rename(2)) is enough. [1]
- Installation to a running system where some library that cannot be
detected, copied and used from the temporary INSTALLTMP with LD_LIBRARY_PATH
that the build itself uses for installation. Such an example is having the
install an NSS module for user lookups that install(1) uses while
concurrently installing the module in another process. This is not
a problem for the FreeBSD base build but can be for downstream
vendors. While this is a very specific case, installation to a
running system with non-atomic library installation is prone to many
problems. A further step still is to install in proper dependency
ordering.
Reported by: dhw many times [1]
Sponsored by: Dell EMC Isilon
MFC after: 2 weeks
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