When installing PHP 5.6 with phpdbg (via Homebrew) on Mac OS, a compile error happens:

/bin/sh /private/tmp/php56-SQBxFw/php-5.6.0/libtool --silent --preserve-dup-deps --mode=compile clang -D_GNU_SOURCE -Isapi/phpdbg/ -I/private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/ -DPHP_ATOM_INC -I/private/tmp/php56-SQBxFw/php-5.6.0/include -I/private/tmp/php56-SQBxFw/php-5.6.0/main -I/private/tmp/php56-SQBxFw/php-5.6.0 -I/private/tmp/php56-SQBxFw/php-5.6.0/ext/date/lib -I/private/tmp/php56-SQBxFw/php-5.6.0/ext/ereg/regex -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/libxml2 -I/usr/local/opt/zlib/include -I/usr/local/opt/jpeg/include -I/usr/local/opt/libpng/include -I/usr/local/Cellar/freetype/2.5.3_1/include/freetype2 -I/usr/local/opt/gettext/include -I/usr/local/Cellar/icu4c/53.1/include -I/private/tmp/php56-SQBxFw/php-5.6.0/ext/mbstring/oniguruma -I/private/tmp/php56-SQBxFw/php-5.6.0/ext/mbstring/libmbfl -I/private/tmp/php56-SQBxFw/php-5.6.0/ext/mbstring/libmbfl/mbfl -I/private/tmp/php56-SQBxFw/php-5.6.0/ext/sqlite3/libsqlite -I/usr/include/libxml2 -I/private/tmp/php56-SQBxFw/php-5.6.0/ext/zip/lib -I/private/tmp/php56-SQBxFw/php-5.6.0/TSRM -I/private/tmp/php56-SQBxFw/php-5.6.0/Zend  -no-cpp-precomp  -I/usr/include -g -O2 -fvisibility=hidden -DZEND_SIGNALS  -c /private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/phpdbg_help.c -o sapi/phpdbg/phpdbg_help.lo
/private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/phpdbg.c:1498:2: error: expected identifier or '('
        if (cleaning || remote) {
        ^
/private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/phpdbg.c:1508:2: error: expected identifier or '('
        if (address) {
        ^
/private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/phpdbg.c:1513:2: error: expected identifier or '('
        if (sapi_name) {
        ^
/private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/phpdbg.c:1520:9: error: a parameter list without types is only allowed in a function definition
        unlink(bp_tmp_file);
               ^
/private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/phpdbg.c:1523:2: error: expected identifier or '('
        return 0;
        ^
/private/tmp/php56-SQBxFw/php-5.6.0/sapi/phpdbg/phpdbg.c:1524:1: error: extraneous closing brace ('}')
} /* }}} */
^
6 errors generated.
make: *** [sapi/phpdbg/phpdbg.lo] Error 1
make: *** Waiting for unfinished jobs....

I was able to workaround the issue by commenting the line 1496 of phpdbg.c. The compilation went thru with no issue after that. I'm not toally sure what should be the right patch, there is a lot of ifdef/ifndef and curly brackets.

I also describe the issue here.