Add FindCrypt.cmake module

This allows to find libcrypt.so by full path, and avoid being dependent
on the compiler directory search.

Re ECFLOW-1987

cmake/Dependencies.cmake

@@ -42,3 +42,15 @@ if (ENABLE_HTTP_COMPRESSION)
     message(FATAL_ERROR "HTTP compression support requested, but zlib was not found")
   endif ()
 endif ()
+
+# =========================================================================================
+# Crypt
+# =========================================================================================
+ecbuild_info( "Locating Crypt" )
+
+find_package(Crypt)
+
+ecbuild_info( "Crypt details:" )
+ecbuild_info( " * Crypt_FOUND        : ${Crypt_FOUND}" )
+ecbuild_info( " * Crypt_INCLUDE_DIRS : ${Crypt_INCLUDE_DIRS}" )
+ecbuild_info( " * Crypt_LIBRARIES    : ${Crypt_LIBRARIES}" )

cmake/FindCrypt.cmake

@@ -0,0 +1,76 @@
+#
+# Copyright 2009- ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+#
+
+# FindCrypt
+# ---------
+#
+
+#
+# Find Crypt library and include dirs
+#
+# Use this module by invoking find_package with the form:
+#
+#   find_package(Crypt
+#     [REQUIRED]             # Fail with error if library is not found
+#   )
+#
+# This module finds headers and libraries, specifying the following variables:
+#
+#   Crypt_FOUND            - True if library is found
+#   Crypt_INCLUDE_DIRS     - Include directories to be used
+#   Crypt_DEFINITIONS      - Compiler flags to be used
+#
+# The following `IMPORTED` targets are also defined:
+#
+#   crypt::crypt          - Generic target for the Crypt library
+#
+#
+
+#
+# -----------------------------------------------------------------------------
+# Search for include DIRs
+# -----------------------------------------------------------------------------
+
+find_path(Crypt_INCLUDE_DIRS
+  NAMES unistd.h
+  HINTS
+    /usr/include)
+
+find_library(Crypt_LIBRARIES
+  NAMES libcrypt.so
+  HINTS
+    /usr/lib)
+
+#
+# -----------------------------------------------------------------------------
+# Handle find_package() REQUIRED and QUIET  parameters
+# -----------------------------------------------------------------------------
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Crypt
+  REQUIRED_VARS
+    Crypt_INCLUDE_DIRS
+    Crypt_LIBRARIES)
+
+#
+# -----------------------------------------------------------------------------
+# Define library as exported targets
+# -----------------------------------------------------------------------------
+
+set(NAME "crypt")
+
+add_library(${NAME} INTERFACE IMPORTED GLOBAL)
+
+set_target_properties(${NAME}
+  PROPERTIES
+    INTERFACE_INCLUDE_DIRECTORIES "${Crypt_INCLUDE_DIRS}"
+    INTERFACE_LINK_LIBRARIES "${Crypt_LIBRARIES}")
+
+add_library(crypt::crypt ALIAS crypt)

libs/CMakeLists.txt

@@ -566,7 +566,7 @@ ecbuild_add_library(
     Boost::date_time
     Boost::program_options
     $<$<BOOL:${OPENSSL_FOUND}>:OpenSSL::SSL>
-    $<$<NOT:$<BOOL:${APPLE}>>:crypt>
+    $<$<BOOL:${Crypt_FOUND}>:crypt::crypt>
     Threads::Threads
   DEFINITIONS
     CMAKE