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The musl dynamic linker saves a pointer to the process' environment value of LD_LIBRARY_PATH very early in startup. When we move/clobber the environment to make more room for ps status strings, we clobber that value and thereby prevent libraries from being found via LD_LIBRARY_PATH, which breaks the use of a temporary installation for testing purposes. To fix, stop collecting usable space for ps status if we notice that the variable we are about to clobber is LD_LIBRARY_PATH. This will result in some reduction in how long the ps status can be, but it's only likely to occur in temporary test contexts, so it doesn't seem like a big problem. In any case, we don't have to do it if we see we are on glibc, which surely is where the majority of our Linux testing is done. Thomas Munro, Bruce Momjian, and Tom Lane, per report from Wolfgang Walther. Back-patch to all supported branches, with the hope that we'll set up a buildfarm animal to test on this platform. Discussion: https://postgr.es/m/fddd1cd6-dc16-40a2-9eb5-d7fef2101488@technowledgy.de
# Generating dummy probes If Postgres isn't configured with dtrace enabled, we need to generate dummy probes for the entries in probes.d, that do nothing. This is accomplished in Unix via the sed script `Gen_dummy_probes.sed`. We used to use this in MSVC builds using the perl utility `psed`, which mimicked sed. However, that utility disappeared from Windows perl distributions and so we converted the sed script to a perl script to be used in MSVC builds. We still keep the sed script as the authoritative source for generating these dummy probes because except on Windows perl is not a hard requirement when building from a tarball. So, if you need to change the way dummy probes are generated, first change the sed script, and when it's working generate the perl script. This can be accomplished by using the perl utility s2p. s2p is no longer part of the perl core, so it might not be on your system, but it is available on CPAN and also in many package systems. e.g. on Fedora it can be installed using `cpan App::s2p` or `dnf install perl-App-s2p`. The Makefile contains a recipe for regenerating Gen_dummy_probes.pl, so all you need to do is once you have s2p installed is `make Gen_dummy_probes.pl` Note that in a VPATH build this will generate the file in the vpath tree, not the source tree.