Allow BAREOS to interface to multiple crypto libs.

OPENSSL gives all kind of headaches as its not compatible to AGPLv3 and
as such you always need a linkage exception in your LICENSE. Allowing
to interface to GNUTLS (LGPL) or Mozilla NSS (MPL/GPL/LGPL) makes this
probem much easier to swallow. This is the first work to allow either
one of the following crypto/TLS frameworks:

- None
- OpenSSL
- GNUTLS
- Mozilla NSS

Also only link and include the crypto specific headers and libs in
the place that actually defines the abstraction layer and not all over
the code.

autoconf/Make.common.in

@@ -78,9 +78,9 @@ LIBTOOL_UNINSTALL = @LIBTOOL@ --silent --tag=$(LIBTOOL_TAG) --mode=uninstall
 LIBTOOL_CLEAN = @LIBTOOL@ --silent --tag=$(LIBTOOL_TAG) --mode=clean
 
 # Flags & libs
-CFLAGS = @CFLAGS@ @OPENSSL_INC@
-CXXFLAGS = @CXXFLAGS@ @OPENSSL_INC@
-CPPFLAGS = @CPPFLAGS@ @OPENSSL_INC@
+CFLAGS = @CFLAGS@
+CXXFLAGS = @CXXFLAGS@
+CPPFLAGS = @CPPFLAGS@
 LDFLAGS = @LDFLAGS@
 TTOOL_LDFLAGS = @TTOOL_LDFLAGS@
 #DEFS = @DEFS@ @LOCAL_DEFS@
@@ -89,7 +89,10 @@ WRAPLIBS = @WRAPLIBS@
 DINCLUDE = @DINCLUDE@
 DLIB = @DLIB@
 PYTHON_LIBS = @PYTHON_LIBS@
+OPENSSL_INCLUDES = @OPENSSL_INC@
 OPENSSL_LIBS = @OPENSSL_LIBS@
+GNUTLS_INCLUDES = @GNUTLS_INC@
+GNUTLS_LIBS = @GNUTLS_LIBS@
 DLLIBS = @LIBADD_DLOPEN@