Christian Böhme writes: > > I am currently trying to install the 4.2.0 version of GCC on a > Linux system that has not seen much administration work over the past > years. This system has an old and broken (apparently misadminstered) > version of g++ installed that is not usable. It also happens that > said system has some commercial production software on it which is > not available in source form. Since I am not going to want to do a > full bootstrap of the whole system, let alone experimenting with > (in)compatibilities of versions of all sorts of runtime libraries > (eg, libc, libstdc++) with said software, the logical approach would > be to install the new compiler in a separate location that is to use > the binutils, runtime linker and libc of the system. Yes. > The problem here is that this new compiler with its updated/ > improved/bug-less runtime libraries (such as libgcc_s.so, > libstdc++.so, libgfortran.so) does not explicitly tell the linker > to link against them (or set DT_RUNPATH in the resulting executables > accordingly) but to use what is setup by the sysadmin (via /etc/ld.so.conf > and friends). Consequently, I reverted back to configuring with static > runtime libraries which even more surprisingly yielded the same result. > It appears that g++ only passes a lone -lstdc++ to the linker > but not the path where GCC supposedly installed its own sparkly > new libraries (either shared or static). > > While it would certainly be _possible_ to set LD_RUN_PATH to the > location of the libraries during link time, it nevertheless is tedious > to do so for every invokation. It would, of course, require knowledge > about their exact location in the filesysytem which is definitely not > what every user should be expected to know. > > What I want is that executables compiled with the new compiler > shall be linked against the new runtime libraries installed with > that compiler while existing software is to use the existing runtime > libraries. > > Is there a way to do that without hacking the GCC sources ? The simplest and probably best idea is the most obvious one: replace your installed gcc with a script that invokes gcc with "-specs=FILE". You can then add any specs you want in FILE, such as invoking ld with -rpath. Andrew.
