install.texi

理解和实践操作系统的一本好书

information, every time it is run.  This is for internal development
purposes, and only works when the compiler is being built with gcc.  The
@var{level} argument controls whether the compiler is built optimized or
not, values are @samp{opt} and @samp{noopt}.  For coverage analysis you
want to disable optimization, for performance analysis you want to
enable optimization.  When coverage is enabled, the default level is
without optimization.

@item --enable-gather-detailed-mem-stats
When this option is specified more detailed information on memory
allocation is gathered.  This information is printed when using
@option{-fmem-report}.

@item --with-gc
@itemx --with-gc=@var{choice}
With this option you can specify the garbage collector implementation
used during the compilation process.  @var{choice} can be one of
@samp{page} and @samp{zone}, where @samp{page} is the default.

@item --enable-nls
@itemx --disable-nls
The @option{--enable-nls} option enables Native Language Support (NLS),
which lets GCC output diagnostics in languages other than American
English.  Native Language Support is enabled by default if not doing a
canadian cross build.  The @option{--disable-nls} option disables NLS@.

@item --with-included-gettext
If NLS is enabled, the @option{--with-included-gettext} option causes the build
procedure to prefer its copy of GNU @command{gettext}.

@item --with-catgets
If NLS is enabled, and if the host lacks @code{gettext} but has the
inferior @code{catgets} interface, the GCC build procedure normally
ignores @code{catgets} and instead uses GCC's copy of the GNU
@code{gettext} library.  The @option{--with-catgets} option causes the
build procedure to use the host's @code{catgets} in this situation.

@item --with-libiconv-prefix=@var{dir}
Search for libiconv header files in @file{@var{dir}/include} and
libiconv library files in @file{@var{dir}/lib}.

@item --enable-obsolete
Enable configuration for an obsoleted system.  If you attempt to
configure GCC for a system (build, host, or target) which has been
obsoleted, and you do not specify this flag, configure will halt with an
error message.

All support for systems which have been obsoleted in one release of GCC
is removed entirely in the next major release, unless someone steps
forward to maintain the port.

@item --enable-decimal-float
@itemx --enable-decimal-float=yes
@itemx --enable-decimal-float=no
@itemx --enable-decimal-float=bid
@itemx --enable-decimal-float=dpd
@itemx --disable-decimal-float
Enable (or disable) support for the C decimal floating point extension
that is in the IEEE 754R extension to the IEEE754 floating point
standard.  This is enabled by default only on PowerPC, i386, and
x86_64 GNU/Linux systems.  Other systems may also support it, but
require the user to specifically enable it.  You can optionally
control which decimal floating point format is used (either @samp{bid}
or @samp{dpd}).  The @samp{bid} (binary integer decimal) format is
default on i386 and x86_64 systems, and the @samp{dpd} (densely packed
decimal) format is default on PowerPC systems.

@item --enable-fixed-point
@itemx --disable-fixed-point
Enable (or disable) support for C fixed-point arithmetic.
This option is enabled by default for some targets (such as MIPS) which
have hardware-support for fixed-point operations.  On other targets, you
may enable this option manually.

@item --with-long-double-128
Specify if @code{long double} type should be 128-bit by default on selected
GNU/Linux architectures.  If using @code{--without-long-double-128},
@code{long double} will be by default 64-bit, the same as @code{double} type.
When neither of these configure options are used, the default will be
128-bit @code{long double} when built against GNU C Library 2.4 and later,
64-bit @code{long double} otherwise.

@item --with-gmp=@var{pathname}
@itemx --with-gmp-include=@var{pathname}
@itemx --with-gmp-lib=@var{pathname}
@itemx --with-mpfr=@var{pathname}
@itemx --with-mpfr-include=@var{pathname}
@itemx --with-mpfr-lib=@var{pathname}
If you do not have GMP (the GNU Multiple Precision library) and the
MPFR Libraries installed in a standard location and you want to build
GCC, you can explicitly specify the directory where they are installed
(@samp{--with-gmp=@var{gmpinstalldir}},
@samp{--with-mpfr=@var{mpfrinstalldir}}).  The
@option{--with-gmp=@var{gmpinstalldir}} option is shorthand for
@option{--with-gmp-lib=@var{gmpinstalldir}/lib} and
@option{--with-gmp-include=@var{gmpinstalldir}/include}.  Likewise the
@option{--with-mpfr=@var{mpfrinstalldir}} option is shorthand for
@option{--with-mpfr-lib=@var{mpfrinstalldir}/lib} and
@option{--with-mpfr-include=@var{mpfrinstalldir}/include}.  If these
shorthand assumptions are not correct, you can use the explicit
include and lib options directly.

@item --with-debug-prefix-map=@var{map}
Convert source directory names using @option{-fdebug-prefix-map} when
building runtime libraries.  @samp{@var{map}} is a space-separated
list of maps of the form @samp{@var{old}=@var{new}}.

@end table

@subheading Cross-Compiler-Specific Options
The following options only apply to building cross compilers.
@table @code
@item --with-sysroot
@itemx --with-sysroot=@var{dir}
Tells GCC to consider @var{dir} as the root of a tree that contains a
(subset of) the root filesystem of the target operating system.
Target system headers, libraries and run-time object files will be
searched in there.  The specified directory is not copied into the
install tree, unlike the options @option{--with-headers} and
@option{--with-libs} that this option obsoletes.  The default value,
in case @option{--with-sysroot} is not given an argument, is
@option{$@{gcc_tooldir@}/sys-root}.  If the specified directory is a
subdirectory of @option{$@{exec_prefix@}}, then it will be found relative to
the GCC binaries if the installation tree is moved.

@item --with-build-sysroot
@itemx --with-build-sysroot=@var{dir}
Tells GCC to consider @var{dir} as the system root (see
@option{--with-sysroot}) while building target libraries, instead of
the directory specified with @option{--with-sysroot}.  This option is
only useful when you are already using @option{--with-sysroot}.  You
can use @option{--with-build-sysroot} when you are configuring with
@option{--prefix} set to a directory that is different from the one in
which you are installing GCC and your target libraries.  

This option affects the system root for the compiler used to build
target libraries (which runs on the build system); it does not affect
the compiler which is used to build GCC itself.

@item --with-headers
@itemx --with-headers=@var{dir}
Deprecated in favor of @option{--with-sysroot}.
Specifies that target headers are available when building a cross compiler.
The @var{dir} argument specifies a directory which has the target include
files.  These include files will be copied into the @file{gcc} install
directory.  @emph{This option with the @var{dir} argument is required} when
building a cross compiler, if @file{@var{prefix}/@var{target}/sys-include}
doesn't pre-exist.  If @file{@var{prefix}/@var{target}/sys-include} does
pre-exist, the @var{dir} argument may be omitted.  @command{fixincludes}
will be run on these files to make them compatible with GCC@.

@item --without-headers
Tells GCC not use any target headers from a libc when building a cross
compiler.  When crossing to GNU/Linux, you need the headers so GCC
can build the exception handling for libgcc.

@item --with-libs
@itemx --with-libs=``@var{dir1} @var{dir2} @dots{} @var{dirN}''
Deprecated in favor of @option{--with-sysroot}.
Specifies a list of directories which contain the target runtime
libraries.  These libraries will be copied into the @file{gcc} install
directory.  If the directory list is omitted, this option has no
effect.

@item --with-newlib
Specifies that @samp{newlib} is
being used as the target C library.  This causes @code{__eprintf} to be
omitted from @file{libgcc.a} on the assumption that it will be provided by
@samp{newlib}.

@item --with-build-time-tools=@var{dir}
Specifies where to find the set of target tools (assembler, linker, etc.)
that will be used while building GCC itself.  This option can be useful
if the directory layouts are different between the system you are building
GCC on, and the system where you will deploy it.

For example, on a @option{ia64-hp-hpux} system, you may have the GNU
assembler and linker in @file{/usr/bin}, and the native tools in a
different path, and build a toolchain that expects to find the
native tools in @file{/usr/bin}.

When you use this option, you should ensure that @var{dir} includes
@command{ar}, @command{as}, @command{ld}, @command{nm},
@command{ranlib} and @command{strip} if necessary, and possibly
@command{objdump}.  Otherwise, GCC may use an inconsistent set of
tools.
@end table

@subheading Java-Specific Options

The following option applies to the build of the Java front end.

@table @code
@item --disable-libgcj
Specify that the run-time libraries
used by GCJ should not be built.  This is useful in case you intend
to use GCJ with some other run-time, or you're going to install it
separately, or it just happens not to build on your particular
machine.  In general, if the Java front end is enabled, the GCJ
libraries will be enabled too, unless they're known to not work on
the target platform.  If GCJ is enabled but @samp{libgcj} isn't built, you
may need to port it; in this case, before modifying the top-level
@file{configure.in} so that @samp{libgcj} is enabled by default on this platform,
you may use @option{--enable-libgcj} to override the default.

@end table

The following options apply to building @samp{libgcj}.

@subsubheading General Options

@table @code
@item --enable-java-maintainer-mode
By default the @samp{libjava} build will not attempt to compile the
@file{.java} source files to @file{.class}.  Instead, it will use the
@file{.class} files from the source tree.  If you use this option you
must have executables named @command{ecj1} and @command{gjavah} in your path
for use by the build.  You must use this option if you intend to
modify any @file{.java} files in @file{libjava}.

@item --with-java-home=@var{dirname}
This @samp{libjava} option overrides the default value of the
@samp{java.home} system property.  It is also used to set
@samp{sun.boot.class.path} to @file{@var{dirname}/lib/rt.jar}.  By
default @samp{java.home} is set to @file{@var{prefix}} and
@samp{sun.boot.class.path} to
@file{@var{datadir}/java/libgcj-@var{version}.jar}.

@item --with-ecj-jar=@var{filename}
This option can be used to specify the location of an external jar
file containing the Eclipse Java compiler.  A specially modified
version of this compiler is used by @command{gcj} to parse
@file{.java} source files.  If this option is given, the
@samp{libjava} build will create and install an @file{ecj1} executable
which uses this jar file at runtime.

If this option is not given, but an @file{ecj.jar} file is found in
the topmost source tree at configure time, then the @samp{libgcj}
build will create and install @file{ecj1}, and will also install the
discovered @file{ecj.jar} into a suitable place in the install tree.

If @file{ecj1} is not installed, then the user will have to supply one
on his path in order for @command{gcj} to properly parse @file{.java}
source files.  A suitable jar is available from
@uref{ftp://sourceware.org/pub/java/}.

@item --disable-getenv-properties
Don't set system properties from @env{GCJ_PROPERTIES}.

@item --enable-hash-synchronization
Use a global hash table for monitor locks.  Ordinarily,
@samp{libgcj}'s @samp{configure} script automatically makes
the correct choice for this option for your platform.  Only use
this if you know you need the library to be configured differently.

@item --enable-interpreter
Enable the Java interpreter.  The interpreter is automatically
enabled by default on all platforms that support it.  This option
is really only useful if you want to disable the interpreter
(using @option{--disable-interpreter}).

@item --disable-java-net
Disable java.net.  This disables the native part of java.net only,
using non-functional stubs for native method implementations.

@item --disable-jvmpi
Disable JVMPI support.

@item --disable-libgcj-bc
Disable BC ABI compilation of certain parts of libgcj.  By default,
some portions of libgcj are compiled with @option{-findirect-dispatch}
and @option{-fno-indirect-classes}, allowing them to be overridden at
run-time.

If @option{--disable-libgcj-bc} is specified, libgcj is built without
these options.  This allows the compile-time linker to resolve
dependencies when statically linking to libgcj.  However it makes it
impossible to override the affected portions of libgcj at run-time.

@item --with-ecos
Enable runtime eCos target support.

@item --without-libffi
Don't use @samp{libffi}.  This will disable the interpreter and JNI
support as well, as these require @samp{libffi} to work.

@item --enable-libgcj-debug
Enable runtime debugging code.

@item --enable-libgcj-multifile
If specified, causes all @file{.java} source files to be
compiled into @file{.class} files in one invocation of
@samp{gcj}.  This can speed up build time, but is more
resource-intensive.  If this option is unspecified or
disabled, @samp{gcj} is invoked once for each @file{.java}
file to compile into a @file{.class} file.

@item --with-libiconv-prefix=DIR
Search for libiconv in @file{DIR/include} and @file{DIR/lib}.

@item --enable-sjlj-exceptions
Force use of the @code{setjmp}/@code{longjmp}-based scheme for exceptions.
@samp{configure} ordinarily picks the correct value based on the platform.
Only use this option if you are sure you need a different setting.

@item --with-system-zlib
Use installed @samp{zlib} rather than that included with GCC@.

@item --with-win32-nlsapi=ansi, unicows or unicode
Indicates how MinGW @samp{libgcj} translates between UNICODE
characters and the Win32 API@.
@table @code
@item ansi
Use the single-byte @code{char} and the Win32 A functions natively,
translating to and from UNICODE when using these functions.  If
unspecified, this is the default.

@item unicows
Use the @code{WCHAR} and Win32 W functions natively.  Adds
@code{-lunicows} to @file{libgcj.spec} to link with @samp{libunicows}.
@file{unicows.dll} needs to be deployed on Microsoft Windows 9X machines
running built executables.  @file{libunicows.a}, an open-source
import library around Microsoft's @code{unicows.dll}, is obtained from
@uref{http://libunicows.sourceforge.net/}, which also gives details
on getting @file{unicows.dll} from