Building on OS X - how?

[Hubert Feyrer <hubert%feyrer.de@localhost>]

Hi,

for a long time I've cross-built -current/amd64 from OS X. After following 
the advice to install Command Line Tools[1] as a second compiler besides 
Xcode, things went downhill and I see different build errors with no 
special build flags, or with various settings like "-V 
HOST_CC=/Developer/usr/bin/cc -V HOST_CXX=/Developer/usr/bin/
c++" (LLVM) and "-V HOST_CC=/usr/bin/cc -V HOST_CXX=/usr/bin/g++" (clang).

I've added a bit more information below[2], but to cut a long story short 
- what excact build.sh options does one use these days to cross-build 
-current/amd64 from OS X? Did I miss any documentation[3]

Thanks in advance!


 - Hubert


[1] https://developer.apple.com/downloads/
    The link is from pkgsrc/bootstrap/README.MacOSX

[2]
% xcode-select -v
xcode-select version 2339.

% uname -a
Darwin promise.local 14.5.0 Darwin Kernel Version 14.5.0: Thu Jun 16 
19:58:21 PDT 2016; root:xnu-2782.50.4~1/RELEASE_X86_64 x86_64

% gcc -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr 
--with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 7.0.2 (clang-700.1.81)
Target: x86_64-apple-darwin14.5.0
Thread model: posix

% /Developer/usr/bin/gcc -v
couldn't understand kern.osversion `14.5.0'
Using built-in specs.
Target: i686-apple-darwin11
Configured with: 
/private/var/tmp/llvmgcc42/llvmgcc42-2336.1~22/src/configure 
--disable-checking --enable-werror --prefix=/Developer/usr/llvm-gcc-4.2 
--mandir=/share/man --enable-languages=c,objc,c++,obj-c++ 
--program-prefix=llvm- --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ 
--with-slibdir=/usr/lib --build=i686-apple-darwin11 
--enable-llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.1~22/dst-llvmCore/Developer/usr/local 
--program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11 
--target=i686-apple-darwin11 --with-gxx-include-dir=/usr/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.1.00)

[3] neither the NetBSD guide nor src/BUILDING provide help on
    cross-building from OS X in particular