Added CPack packaging and fix Linux compatibility.

- configure wrapper had bash syntax some places; replaced w/ sh syntax
- Added FindOpenSSL module.  The one that ships with CMake does not
  allow for specifying a non-standard location.
- datadir configure option changed to be relative to prefix.  This
  simplifies the packaging from having to consider absolute paths.
- Added macro for changing install_name of shared libs that need to
  ship with precompiled Bro for OS X.  This is only the optional
  libmagic and libGeoIP for now.

cmake/FindOpenSSL.cmake

@@ -0,0 +1,56 @@
+# - Try to find openssl include dirs and libraries 
+#
+# Usage of this module as follows:
+#
+#     find_package(OpenSSL)
+#
+# Variables used by this module, they can change the default behaviour and need
+# to be set before calling find_package:
+#
+#  OpenSSL_ROOT_DIR          Set this variable to the root installation of
+#                            openssl if the module has problems finding the
+#                            proper installation path.
+#
+# Variables defined by this module:
+#
+#  OpenSSL_FOUND             System has openssl, include and library dirs found
+#  OpenSSL_INCLUDE_DIR       The openssl include directories. 
+#  OpenSSL_LIBRARIES         The openssl libraries.
+#  OpenSSL_CYRPTO_LIBRARY    The openssl crypto library.
+#  OpenSSL_SSL_LIBRARY       The openssl ssl library.
+
+find_path(OpenSSL_ROOT_DIR
+    NAMES include/openssl/ssl.h
+)
+
+find_path(OpenSSL_INCLUDE_DIR
+    NAMES openssl/ssl.h
+    HINTS ${OpenSSL_ROOT_DIR}/include
+)
+
+find_library(OpenSSL_SSL_LIBRARY
+    NAMES ssl ssleay32 ssleay32MD
+    HINTS ${OpenSSL_ROOT_DIR}/lib
+)
+
+find_library(OpenSSL_CRYPTO_LIBRARY
+    NAMES crypto
+    HINTS ${OpenSSL_ROOT_DIR}/lib
+)
+
+set(OpenSSL_LIBRARIES ${OpenSSL_SSL_LIBRARY} ${OpenSSL_CRYPTO_LIBRARY}
+    CACHE STRING "OpenSSL SSL and crypto libraries" FORCE)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(OpenSSL DEFAULT_MSG
+    OpenSSL_LIBRARIES
+    OpenSSL_INCLUDE_DIR
+)
+
+mark_as_advanced(
+    OpenSSL_ROOT_DIR
+    OpenSSL_INCLUDE_DIR
+    OpenSSL_LIBRARIES
+    OpenSSL_CRYPTO_LIBRARY
+    OpenSSL_SSL_LIBRARY
+)