papadave via Gcc-help kirjoitti 22.9.2020 klo 17.41:
Hello,
Recently I was trying to cross build a latest gcc on FreeBSD amd64 ,and
target is x86_64 Solaris. I built the binutils with following configure:
../configure --build=x86_64-unknown-freebsd12
--target=x86_64-unknown-solaris2.11 --prefix=/opt/toolchains
--sysconfdir=/etc --localstatedir=/var --libexecdir='${prefix}/lib'
--with-system-zlib --with-gmp=/usr/local --with-mpfr=/usr/local
--disable-rpath --enable-deterministic-archives --enable-nls --enable-gold
--enable-ld --enable-plugins
Later I configured the gcc in a new subdirectory as follows:
../gcc-10.2.0/configure --build=x86_64-unknown-freebsd12
--target=x86_64-unknown-solaris2.11 --disable-bootstrap
--enable-gnu-indirect-function --prefix=/opt/toolchains --sysconfdir=/etc
--localstatedir=/var --libexecdir='${prefix}/lib/gcc' --disable-rpath
--program-prefix=x86_64-unknown-solaris2.11- --program-suffix=-10.2
--with-gnu-as --with-gnu-ld --with-gmp=/usr/local --with-pkgversion=Rivoreo
--with-system-zlib --enable-languages=c,c++,objc,fortran,obj-c++,go
--enable-multilib
Ok, for a crosscompiler one needs just the same target C library stuff
(here for
x86_64-unknown-solaris2.11) as is needed in a native GCC build for the
target.
Usually it will be copied/unpacked into a chosen $sysroot on the host
machine
(here x86_64-unknown-freebsd12). And a "--with-sysroot=$sysroot" option is
given both in binutils and GCC configure commands to tell to "ld" and "gcc"
where the target libraries and headers are. In your case choosing the
"/opt/toolchains/host-x86_64-unknown-solaris2.11" as the $sysroot could be
one choice if your aim is to put more crosstoolchains for all kind of
targets into
the "/opt/toolchains". And use the "/opt/toolchains/host-$target" as the
standard for the install places for their C libraries.
I remember the "native install" for Solaris2.x C library being quite
complicated so using
the default "$prefix/$target/include" and "$prefix/$target/lib" would
need some
scratching of one's head to get everything in the Solaris2.x C library
being found
there. Much easier is to let it be similar to the native scheme in the
$sysroot
(the cross "/" is the $sysroot on the host system).
-B/opt/toolchains/x86_64-unknown-solaris2.11/bin/
-B/opt/toolchains/x86_64-unknown-solaris2.11/lib/
-isystem /opt/toolchains/x86_64-unknown-solaris2.11/include
-isystem /opt/toolchains/x86_64-unknown-solaris2.11/sys-include
These tell where the target C library will be searched now. Please don't
ask for what
purpose the "sys-include" is there. Just take it as a relic from the
ancient time when
someone maybe knew why he/she needed it :) The funny thing is that it
will be searched
before the "include" unless the order is the same as given in the
"-isystem <dir>" options
(the old order was changed in the 'gcc/cppdefaults.c' or something).
