Some libstdc++ headers are installed in GPLUSPLUS_TOOL_INCLUDE_DIR, i.e.
include/c++/version/target. These headers are derived from information
configured separately for each multilib, and in general may differ between
multilibs, so should go in a multilib directory (e.g.
include/c++/version/target/multilib). The precompiled headers installed there,
in particular, should be separately installed for each multilib in all cases,
even if in some cases the actual text headers happen to be the same for each
multilib.
One possible plan for fixing this is to add a flag to struct default_include
meaning "add a multilib suffix to this include directory", then make the driver
pass a -imultilib option to cc1plus which provides the suffix appended to
GPLUSPLUS_TOOL_INCLUDE_DIR. libstdc++-v3 would then need to be taught to
install the headers in the multilib subdirectory instead of directly in
include/c++/version/target. (The build directory arrangement can stay the
same, since each multilib gets built in its own directory.)
--
Summary: libstdc++ headers should go in multilib directories
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jsm28 at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25524
