Quick note:  I've seen this before, and it was on a Solaris 2.7 box, running GCC3.  Has anybody else had this problem?

GCC Version:  3.0 (Single threaded)
Flex Version: 2.5.4
Make Version: 3.79.1

Error information:

root@oracle:/usr/src/php-4.0.6# make
Making all in Zend
make[1]: Entering directory `/usr/src/php-4.0.6/Zend'
/bin/sh ../libtool --silent --mode=compile c++ -DHAVE_CONFIG_H -I. -I. -I../main   -D_REENTRANT -DSUPPORT_UTF8 -DXML_BYTE_ORDER=12 -I../TSRM  -g -O2 -pthread -c zend_language_scanner_cc.cc
In file included from FlexLexer.h:47,
                 from zend_language_scanner_cc.cc:240:
/usr/local/include/g++-v3/backward/iostream.h:36: using directive `istream'
   introduced ambiguous type `istream'
In file included from zend_language_scanner_cc.cc:2712:
zend_istdiostream.h:8: 'stdiobuf' is used as a type, but is not defined as a
   type.
zend_istdiostream.h:11: syntax error before `*' token
zend_istdiostream.h: In constructor `istdiostream::istdiostream(FILE*)':
zend_istdiostream.h:10: class `istdiostream' does not have any field named
   `_file'
zend_istdiostream.h:10: no matching function for call to
   `std::basic_istream<char, std::char_traits<char> >::basic_istream()'
/usr/local/include/g++-v3/bits/std_istream.h:209: candidates are:
   std::basic_istream<_CharT, _Traits>::basic_istream(const
   std::basic_istream<_CharT, _Traits>&) [with _CharT = char, _Traits =
   std::char_traits<char>]
/usr/local/include/g++-v3/bits/std_istream.h:72:
   std::basic_istream<_CharT,
   _Traits>::basic_istream(std::basic_streambuf<_CharT, _Traits>*) [with _CharT
   = char, _Traits = std::char_traits<char>]
zend_istdiostream.h:10: `_file' undeclared (first use this function)
zend_istdiostream.h:10: (Each undeclared identifier is reported only once for
   each function it appears in.)
zend_istdiostream.h: At global scope:
zend_istdiostream.h:12: parse error before `}' token
zend_language_scanner_cc.cc: In function `void
   zend_file_handle_dtor(zend_file_handle*)':
zend_language_scanner_cc.cc:2823: no matching function for call to
   `std::basic_streambuf<char, std::char_traits<char> >::stdiofile()'
zend_language_scanner_cc.cc: In function `int
   open_file_for_scanning(zend_file_handle*, zend_compiler_globals*)':
zend_language_scanner_cc.cc:2894: no matching function for call to
   `std::basic_ifstream<char, std::char_traits<char> >::basic_ifstream(int&)'
/usr/local/include/g++-v3/bits/std_iosfwd.h:81: candidates are:
   std::basic_ifstream<char, std::char_traits<char> >::basic_ifstream(const
   std::basic_ifstream<char, std::char_traits<char> >&)
/usr/local/include/g++-v3/bits/std_fstream.h:258:
   std::basic_ifstream<_CharT, _Traits>::basic_ifstream(const char*,
   std::_Ios_Openmode = std::ios_base::in) [with _CharT = char, _Traits =
   std::char_traits<char>]
/usr/local/include/g++-v3/bits/std_fstream.h:253:
   std::basic_ifstream<_CharT, _Traits>::basic_ifstream() [with _CharT = char,
   _Traits = std::char_traits<char>]
zend_language_scanner_cc.cc: In member function `int
   ZendFlexLexer::lex_scan(zval*, zend_compiler_globals*)':
zend_language_scanner_cc.cc:4705: cannot convert `std::istream*' to `istream*'
   in assignment
zend_language_scanner_cc.cc: In member function `void
   zendFlexLexer::yy_load_buffer_state()':
zend_language_scanner_cc.cc:5241: cannot convert `istream*' to `std::istream*'
   in assignment
zend_language_scanner_cc.cc: In member function `void
   zendFlexLexer::yy_init_buffer(yy_buffer_state*, std::istream*)':
zend_language_scanner_cc.cc:5292: cannot convert `std::istream*' to `istream*'
   in assignment
make[1]: *** [zend_language_scanner_cc.lo] Error 1
make[1]: Leaving directory `/usr/src/php-4.0.6/Zend'
make: *** [all-recursive] Error 1