In message <[EMAIL PROTECTED]> "John W. Eaton" <[EMAIL PROTECTED]> wrote:
> What is the right way to use autoconf to determine the compiler and > system characteristics for tools that are written in C and must be run > as part of a larger build that is cross compiled? > > For example, Octave has some programs that are written in C++ that are > compiled and run during the build process to generate some > documentation. Thse programs should not be compiled by the cross > compiler tools, but by the normal build system tools so they will run > on the build system (they are not needed on the host system). This is > a simple case because the programs are also simple, and don't rely on > any OS-specific features. > > In a more general case, I suppose you would also need to check > features for the two systems (host and build) separately, and try to > keep track of the results separately. > > If necessary, I could put these tools in a separate directory with an > independent configure script, but then what is the correct way to tell > configure that it should ignore any setting of host and not set up for > cross compiling? This is the approach that I have taken: AC_MSG_NOTICE([configuring the tools for *native* builds]) cd tools && \ ./configure --build=$build_alias --host=$build_alias --target=$host_alias There were no options I needed to pass down to the subdirectory, so this is a gigantic hack - but it works enough for what I needed to do. The key is to base --host and --target on the build and host aliases respectively. You could pass all the configure scripts parameters as long as you put those in front of the explicit --build --host and --target parameters so that these ones take precedence. Another approach I have seen is software relying on a separate environment variable to indicate the native C compiler to use. Various names are used for this CC_FOR_BUILD or BUILD_CC. -- Stewart Brodie, Senior Software Engineer Pace Micro Technology PLC Cambridge, CB5 8PB, United Kingdom http://www.pace.co.uk
