[xmlsec] Minor bug in windows build environment

[Matthias Jung]

Igor,

compiling xmlsec1.0.3 on Windows, not using Xslt
will cause a compile error because the flag /DXMLSEC_NO_XSLT=1
is not correctly set.

This flag is added to the global CFLAGS variable before common settings 
are done.
Adding common settings to CFLAGS will overwrite the no xslt definition.

See:
CFLAGS = /nologo /D "WIN32" /D "_WINDOWS" /D "_MBCS" /D "_REENTRANT" /W3 
$(XMLSEC_CRYPTO_CFLAGS)

Fixing this is quite simple (CFLAGS = $(CFLAGS) /nologo ...... ).
Just wanted to mention it.

Cheers

    Matthias