Fix compile errors on redhat and fix warnings.

Specific error fixed is:
  "error: ‘openssl’ undeclared (first use in this function"

Seems like different unix variants do different things with
escaping of the cflags when executing make. In this case, the
"openssl" was being set by the XMLSEC_CRYPTO macro via a -D flag
to the compiler. xmlsec1-config generates -DXMLSEC_CRYPTO="openssl"
when it really should be generating XMLSEC_CRYPTO=\\"openssl\\"
(really, xmlsec1-config would be more robust if it genreated
-DXMLSEC_CRYPTO=openssl and then xmlsec1 can use the # modifier
to quote the strong).

Also removed -fvisibility-hidden-inlines since that's C++ only.

Lastly correctly implementation of hasXmlSecLastError().