The extensions are build as shared to only check that they compile,
without running tests. The OCI8 extension does not properly SKIPIF
no database is available.
It should be noted that if we do want to also test these, then
(apart from running a database) it will also be necessary to configure
with LIBS="-Wl,--disable-new-dtags" in order to force the use of RPATH
instead of RUNPATH, the latter of which does not affect dlopened
libraries. Using LD_LIBRARY_PATH does not mesh well with our test
suite.
Closes GH-6604.
This uses a separate job template, because msan requires all used
libraries (apart from glibc) to be instrumented, so we can't link
any external libraries unless we recompile them. As such, we need
a much more minimal configure.