Took a while to track this conflict down while trying to install RethinkDB...

gistfile1.txt

% brew install boost (add --interactive to be able to view bootstrap.log!)

    ./bootstrap.sh --prefix=/usr/local/Cellar/boost/1.53.0 --libdir=/usr/local/Cellar/boost/1.53.0/lib --without-icu
    -n Building Boost.Build engine with toolset darwin... 
    Failed to build Boost.Build build engine
    Consult 'bootstrap.log' for more details



Fix, via https://github.com/mxcl/homebrew/issues/12457#issuecomment-5992798:

    > The problem is that the go formula installs a conflicting ar.h
    > header file that is then picked up during builds. - jacknagel

% brew uninstall go
% brew install boost

    ...

    /usr/local/Cellar/rethinkdb/1.6.1: 168 files, 25M, built in 4.7 minutes

Success! Thanks jacknagel!





bootstrap.log:

###
### Using 'darwin' toolset.
###
rm -rf bootstrap
mkdir bootstrap
cc -o bootstrap/jam0 command.c compile.c constants.c debug.c function.c glob.c hash.c hdrmacro.c headers.c jam.c jambase.c jamgram.c lists.c make.c make1.c object.c option.c output.c parse.c pathunix.c regexp.c rules.c scan.c search.c subst.c timestamp.c variable.c modules.c strings.c filesys.c builtins.c pwd.c class.c native.c md5.c w32_getreg.c modules/set.c modules/path.c modules/regex.c modules/property-set.c modules/sequence.c modules/order.c execunix.c fileunix.c
function.c:3109:31: warning: format specifies type 'char *' but the argument has type 'OBJECT *' (aka 'struct _object *') [-Wformat]
                printf( "%s", formal_arg->arg_name );
                         ~~   ^~~~~~~~~~~~~~~~~~~~
1 warning generated.
make.c:273:37: warning: adding 'int' to a string does not append to the string [-Wstring-plus-int]
        printf( "make\t--\t%s%s\n", spaces( depth ), object_str( t->name ) );
                                    ^~~~~~~~~~~~~~~
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
make.c:273:37: note: use array indexing to silence this warning
        printf( "make\t--\t%s%s\n", spaces( depth ), object_str( t->name ) );
                                    ^
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                                            ^
make.c:280:37: warning: adding 'int' to a string does not append to the string [-Wstring-plus-int]
        printf( "make\t--\t%s%s\n", spaces( depth ), object_str( t->name ) );
                                    ^~~~~~~~~~~~~~~
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
make.c:280:37: note: use array indexing to silence this warning
        printf( "make\t--\t%s%s\n", spaces( depth ), object_str( t->name ) );
                                    ^
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                                            ^
make.c:351:17: warning: adding 'int' to a string does not append to the string [-Wstring-plus-int]
                spaces( depth ), object_str( t->name ), object_str( t->boundname ) );
                ^~~~~~~~~~~~~~~
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
make.c:351:17: note: use array indexing to silence this warning
                spaces( depth ), object_str( t->name ), object_str( t->boundname ) );
                ^
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                                            ^
make.c:359:17: warning: adding 'int' to a string does not append to the string [-Wstring-plus-int]
                spaces( depth ), object_str( t->name ), target_bind[ (int) t->binding ] );
                ^~~~~~~~~~~~~~~
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
make.c:359:17: note: use array indexing to silence this warning
                spaces( depth ), object_str( t->name ), target_bind[ (int) t->binding ] );
                ^
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                                            ^
make.c:364:17: warning: adding 'int' to a string does not append to the string [-Wstring-plus-int]
                spaces( depth ), object_str( t->name ), ctime( &t->time ) );
                ^~~~~~~~~~~~~~~
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
make.c:364:17: note: use array indexing to silence this warning
                spaces( depth ), object_str( t->name ), ctime( &t->time ) );
                ^
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                                            ^
make.c:645:13: warning: adding 'int' to a string does not append to the string [-Wstring-plus-int]
            spaces( depth ), object_str( t->name ) );
            ^~~~~~~~~~~~~~~
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
make.c:645:13: note: use array indexing to silence this warning
            spaces( depth ), object_str( t->name ) );
            ^
make.c:102:45: note: expanded from macro 'spaces'
# define spaces(x) ( "                    " + ( x > 20 ? 0 : 20-x ) )
                                            ^
6 warnings generated.
fileunix.c:303:33: error: no member named 'ar_fmag' in 'struct ar_hdr'
           && !( memcmp( ar_hdr.ar_fmag, ARFMAG, SARFMAG )
                         ~~~~~~ ^
fileunix.c:320:35: error: no member named 'ar_name' in 'struct ar_hdr'
        strncpy( lar_name, ar_hdr.ar_name, sizeof(ar_hdr.ar_name) );
                           ~~~~~~ ^
/usr/include/secure/_string.h:124:37: note: expanded from macro 'strncpy'
   ? __builtin___strncpy_chk (dest, src, len, __darwin_obsz (dest))     \
                                    ^
fileunix.c:320:35: error: no member named 'ar_name' in 'struct ar_hdr'
        strncpy( lar_name, ar_hdr.ar_name, sizeof(ar_hdr.ar_name) );
                           ~~~~~~ ^
/usr/include/secure/_string.h:125:34: note: expanded from macro 'strncpy'
   : __inline_strncpy_chk (dest, src, len))
                                 ^
fileunix.c:322:24: error: no member named 'ar_date' in 'struct ar_hdr'
        sscanf( ar_hdr.ar_date, "%ld", &lar_date );
                ~~~~~~ ^
fileunix.c:323:24: error: no member named 'ar_size' in 'struct ar_hdr'
        sscanf( ar_hdr.ar_size, "%ld", &lar_size );
                ~~~~~~ ^
fileunix.c:325:20: error: no member named 'ar_name' in 'struct ar_hdr'
        if (ar_hdr.ar_name[0] == '/')
            ~~~~~~ ^
fileunix.c:327:20: error: no member named 'ar_name' in 'struct ar_hdr'
        if (ar_hdr.ar_name[1] == '/')
            ~~~~~~ ^
fileunix.c:339:41: error: no member named 'ar_name' in 'struct ar_hdr'
        else if (string_table && ar_hdr.ar_name[1] != ' ')
                                 ~~~~~~ ^
8 errors generated.