[pcre-dev] [pcrecpp] building dll - Warning: needs to have …

Hello there,

I get 3 of these warnings when building DLL using /MT option.
Using Visual Studio 2008 SP1. I've generated the solution using CMAKE.
These warnings started appearing after my change to Runtime Library option:
from /MD => /MT.

Should I worry about these warnings or can I ignore them?

Here is the build log:
-----------------------------

Compiling...
pcre_stringpiece.cc
pcre_scanner.cc
D:\boovix6\win32\pcre\pcrecpp.h(701) : warning C4251:
'pcrecpp::RE::pattern_' : class 'std::basic_string<_Elem,_Traits,_Ax>' needs
to have dll-interface to be used by clients of class 'pcrecpp::RE'
        with
        [
            _Elem=char,
            _Traits=std::char_traits,
            _Ax=std::allocator
        ]
d:\boovix6\win32\pcre\pcre_scanner.h(150) : warning C4251:
'pcrecpp::Scanner::data_' : class 'std::basic_string<_Elem,_Traits,_Ax>'
needs to have dll-interface to be used by clients of class
'pcrecpp::Scanner'
        with
        [
            _Elem=char,
            _Traits=std::char_traits,
            _Ax=std::allocator
        ]
pcrecpp.cc
d:\boovix6\win32\pcre\pcrecpp.h(701) : warning C4251:
'pcrecpp::RE::pattern_' : class 'std::basic_string<_Elem,_Traits,_Ax>' needs
to have dll-interface to be used by clients of class 'pcrecpp::RE'
        with
        [
            _Elem=char,
            _Traits=std::char_traits,
            _Ax=std::allocator
        ]
Generating Code...
Linking...
   Creating library D:\boovix6\win32\pcre\lib\Release\pcrecpp.lib and object
D:\boovix6\win32\pcre\lib\Release\pcrecpp.exp
Embedding manifest...

--
Cheers,
Cezary.