
                              Configuring egcs
                                      
   Like most GNU software, egcs must be configured before it can be
   built. This document attempts to describe the recommended
   configuration procedure for both native and cross targets.
   
   We use srcdir to refer to the toplevel source directory for egcs; we
   use objdir to refer to the toplevel build/object directory for egcs.
   
   First, we highly recommend that egcs be built into a separate
   directory than the sources which does not reside within the source
   tree. This is how we generally build egcs; building where srcdir ==
   objdir should still work, but doesn't get extensive testing; building
   where objdir is a subdirectory of srcdir is unsupported.
   
   Second, when configuring a native system, either "cc" must be in your
   path or you must set CC in your environment before running configure.
   Otherwise the configuration scripts may fail.
   
   To configure egcs:
   
     
     % mkdir objdir
     % cd objdir
     % srcdir/configure [target] [options]
     
   target specification
     * egcs has code to correctly determine the correct value for target
       for nearly all native systems. Therefore, we highly recommend you
       not provide a configure target when configuring a native compiler.
     * target must be specified when configuring a cross compiler;
       examples of valid targets would be i960-rtems, m68k-coff, sh-elf,
       etc.
       
   options specification
   
   Use options to override several configure time options for egcs. A
   partial list of supported options:
     * --prefix=dirname -- Specify the toplevel installation directory.
       This is the recommended way to install the tools into a directory
       other than the default. The toplevel installation directory
       defaults to /usr/local.
       These additional options control where certain parts of the
       distribution are installed. Normally you should not need to use
       these options.
          + --with-local-prefix=dirname -- Specify the installation
            directory for local include files. The default is /usr/local.
          + --with-gxx-include-dir=dirname -- Specify the installation
            directory for g++ header files. The default is
            /usr/local/include/g++.
     * --enable-shared -- Build shared versions of the C++ runtime
       libraries if supported --disable-shared is the default.
     * --enable-haifa -- Enable the new Haifa instruction scheduler in
       the compiler; the new scheduler can significantly improve code on
       some targets.
       For egcs-1.0.x releases --disable-haifa is the default on all
       platforms except the HPPA.
       For newer releases --disable-haifa is the default on all platforms
       except the alpha, hppa, powerpc, rs6000, sparc and m32r.
     * --with-gnu-as -- Specify that the compiler should assume the GNU
       assembler (aka gas) is available.
     * --with-gnu-ld -- Specify that the compiler should assume the GNU
       linker (aka gld) is available.
     * --with-stabs -- Specify that stabs debugging information should be
       used instead of whatever format the host normally uses. Normally
       GCC uses the same debug format as the host system.
     * --enable-multilib -- Specify that multiple target libraries should
       be built to support different target variants, calling
       conventions, etc. This is the default.
     * --enable-threads -- Specify that the target supports threads. This
       only effects the Objective-C compiler and runtime library.
     * --enable-threads=lib -- Specify that lib is the thread support
       library. This only effects the Objective-C compiler and runtime
       library.
     * --with-cpu=cpu -- Specify which cpu variant the compiler should
       generate code for by default. This is currently only supported on
       the RS6000/PowerPC ports.
       
   Some options which only apply to building cross compilers:
     * --with-headers=dir -- Specifies a directory which has target
       include files.
     * --with-libs=dirs -- Specifies a list of directories which contain
       the target runtime libraries.
     * --with-newlib -- Specifies that "newlib" is being used as the
       target C library. This causes __eprintf to be omitted from
       libgcc.a on the assumption that it will be provided by newlib.
       
   Note that each --enable option has a corresponding --disable option
   and that each --with option has a corresponding --without option.
   
     _________________________________________________________________
                                      
   Last modified on May 7, 1998.
