I have 2 dependent packages who should be placed in the same target. Package B is dependent on package A.
Package A can be relocated to any another location. I now want
Hah. So I did a bit of source diving and discovered that apparently (at least for rpm 4.8.0 I didn't look at other versions) the RPM_INSTALL_PREFIX
and RPM_INSTALL_PREFIX#
environment variables are set for the %pre
(and possibly other scriptlets) to the values of (what appear to be the %{INSTPREFIXES}
and/or %{INSTALLPREFIX}
macros). [source link]
I would try those in your %pre
script. They look like they will give you what you want.
Same code in rpm head.