On Tue, Jan 20, 2009 at 2:57 PM, Rene Gollent <anevilyak@xxxxxxxxx> wrote: > They can, the specifics were mentioned in a reply to the svn commit > which enabled that feature, I can try to dig that up for you in a bit. To be exact, it was r25536: "Log: Support for adding libraries compiled with the alternative gcc (2 vs. 4). One has to have a (fully configured) "generated" directory for the alternative gcc and specify it using the new option "--alternative-gcc-output-dir" when configuring the main build. Additionally the build variable HAIKU_ADD_ALTERNATIVE_GCC_LIBS has to be set to "1". If that has been done, when building the image a sub-jam is invoked that generates the alternative libs and zips them. The main-jam unzips them into the correct directory in the image. Note that the JAM build variable has to be set when using a jam executable not invoked by "jam". Tested with gcc 2 NetPositive, Pe, and FireFox under gcc 4 Haiku, and with a few of the standard gcc 4 Haiku apps under gcc 2 Haiku. Seems to work fine so far. " And further clarification from the ensuing discussion: "You have to run configure in that directory first. E.g. setting up output directories for gcc 2 and gcc 4 builds could look like that: cd /path/to/haiku/sources mkdir generated-gcc2 generated-gcc4 cd generated-gcc2 ../configure --build-cross-tools ... --alternative-gcc-output-dir ../generated-gcc4 cd ../generated-gcc4 ../configure --build-cross-tools-gcc4 ... --alternative-gcc-output-dir ../generated-gcc2 "configure" creates a Jamfile in the output directory, and one usually runs jam there. When building an image with the alternative libraries the Jamfile in the other output directory is required, since a sub-jam is invoked there. Note that before this revision no Jamfile was created in "generated" when running "configure" in the source directory. That is you'll have to re-configure this directory, if you want to use it as --alternative-gcc-output-dir for another directory (use --cross-tools-prefix to avoid rebuilding the cross tools)." HTH, Rene