External libraries for Windows are now built automatically in the
qpdf/external-libs repository and include openssl in addition to zlib
and jpeg. Use these, and update the Windows build to build with the
openssl crypto provider by default. We leave the native crypto
provider enabled in case there is a problem with openssl and also to
continue to exercise that code.
- Checks explicitly for versions >= 1.1.0 with pkg-config
- Refactor the fallback checks. Previously they were copied
from the gnutls logic, but could be slightly surprising (it's not
obvious that they're for the case where pkg-config returns a false
negative, and it's weird that the linker check overode the header check)
- Fix the AC_SEARCH_LIBS check to try -lcrypto instead of -lopenssl
(-lcrypto is the standard library OpenSSL ships the crypto symbols in).
- Fix the AC_SEARCH_LIBS check to look for EVP_MD_CTX_new, which is not
present in versions prior to 1.1.0.
Fixes qpdf/qpdf#429 (although I haven't verified on cygwin)
For wildcard expansion to work properly with the msvc binary, it is
necessary to link with setargv.obj or wsetargv.obj, depending on
whether wmain is in use.
Includes updates to m4/ax_cxx_compile_stdcxx.m4 to make it work with
msvc, which supports C++-11 with no flags but doesn't set __cplusplus
to a recent value.
If set, we avoid using Windows I/O HANDLE, which is disallowed in some
versions of the Windows SDK, such as for Windows phones.
QUtil::same_file will always return false in this case. Only applies
to Windows builds.
