Replaced FindNettle.cmake to fix MacOS build

cmake/Modules/FindNettle.cmake

@@ -1,17 +1,142 @@
-if (NOT TARGET Nettle::Nettle)
-	find_path(NETTLE_INCLUDE_DIR nettle/hmac.h)
-	find_library(NETTLE_LIBRARY NAMES nettle libnettle)
-
-	include(FindPackageHandleStandardArgs)
-	find_package_handle_standard_args(Nettle DEFAULT_MSG NETTLE_LIBRARY NETTLE_INCLUDE_DIR)
-
-    if (Nettle_FOUND)
-        add_library(Nettle::Nettle UNKNOWN IMPORTED)
-        set_target_properties(Nettle::Nettle PROPERTIES
-            IMPORTED_LOCATION "${NETTLE_LIBRARY}"
-            INTERFACE_INCLUDE_DIRECTORIES "${NETTLE_INCLUDE_DIRS}"
-            INTERFACE_LINK_LIBRARIES "${NETTLE_LIBRARIES}"
-                IMPORTED_LINK_INTERFACE_LANGUAGES "C")
-    endif ()
-endif ()
+# Copyright (C) 2020 Dieter Baron and Thomas Klausner
+#
+# The authors can be contacted at <[email protected]>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in
+#   the documentation and/or other materials provided with the
+#   distribution.
+#
+# 3. The names of the authors may not be used to endorse or promote
+#   products derived from this software without specific prior
+#   written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
+# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
+# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+# GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+# IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+# IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#[=======================================================================[.rst:
+FindNettle
+-------
+
+Finds the Nettle library.
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+This module provides the following imported targets, if found:
+
+``Nettle::Nettle``
+  The Nettle library
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+This will define the following variables:
+
+``Nettle_FOUND``
+  True if the system has the Nettle library.
+``Nettle_VERSION``
+  The version of the Nettle library which was found.
+``Nettle_INCLUDE_DIRS``
+  Include directories needed to use Nettle.
+``Nettle_LIBRARIES``
+  Libraries needed to link to Nettle.
+
+Cache Variables
+^^^^^^^^^^^^^^^
+
+The following cache variables may also be set:
+
+``Nettle_INCLUDE_DIR``
+  The directory containing ``nettle/aes.h``.
+``Nettle_LIBRARY``
+  The path to the Nettle library.
+
+#]=======================================================================]
+
+find_package(PkgConfig)
+pkg_check_modules(PC_Nettle QUIET nettle)
+
+find_path(Nettle_INCLUDE_DIR
+  NAMES nettle/aes.h nettle/md5.h nettle/pbkdf2.h nettle/ripemd160.h nettle/sha.h
+  PATHS ${PC_Nettle_INCLUDE_DIRS}
+)
+find_library(Nettle_LIBRARY
+  NAMES nettle
+  PATHS ${PC_Nettle_LIBRARY_DIRS}
+)
+
+# Extract version information from the header file
+if(Nettle_INCLUDE_DIR)
+  # This file only exists in nettle>=3.0
+  if(EXISTS ${Nettle_INCLUDE_DIR}/nettle/version.h)
+    file(STRINGS ${Nettle_INCLUDE_DIR}/nettle/version.h _ver_major_line
+         REGEX "^#define NETTLE_VERSION_MAJOR  *[0-9]+"
+         LIMIT_COUNT 1)
+    string(REGEX MATCH "[0-9]+"
+           Nettle_MAJOR_VERSION "${_ver_major_line}")
+    file(STRINGS ${Nettle_INCLUDE_DIR}/nettle/version.h _ver_minor_line
+         REGEX "^#define NETTLE_VERSION_MINOR  *[0-9]+"
+         LIMIT_COUNT 1)
+    string(REGEX MATCH "[0-9]+"
+           Nettle_MINOR_VERSION "${_ver_minor_line}")
+    set(Nettle_VERSION "${Nettle_MAJOR_VERSION}.${Nettle_MINOR_VERSION}")
+    unset(_ver_major_line)
+    unset(_ver_minor_line)
+  else()
+    if(PC_Nettle_VERSION)
+      set(Nettle_VERSION ${PC_Nettle_VERSION})
+    else()
+      set(Nettle_VERSION "1.0")
+    endif()
+  endif()
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Nettle
+  FOUND_VAR Nettle_FOUND
+  REQUIRED_VARS
+    Nettle_LIBRARY
+    Nettle_INCLUDE_DIR
+  VERSION_VAR Nettle_VERSION
+)
+
+if(Nettle_FOUND)
+  set(Nettle_LIBRARIES ${Nettle_LIBRARY})
+  set(Nettle_INCLUDE_DIRS ${Nettle_INCLUDE_DIR})
+  set(Nettle_DEFINITIONS ${PC_Nettle_CFLAGS_OTHER})
+endif()
+
+if(Nettle_FOUND AND NOT TARGET Nettle::Nettle)
+  add_library(Nettle::Nettle UNKNOWN IMPORTED)
+  set_target_properties(Nettle::Nettle PROPERTIES
+    IMPORTED_LOCATION "${Nettle_LIBRARY}"
+    INTERFACE_COMPILE_OPTIONS "${PC_Nettle_CFLAGS_OTHER}"
+    INTERFACE_INCLUDE_DIRECTORIES "${Nettle_INCLUDE_DIR}"
+  )
+endif()
+
+mark_as_advanced(
+  Nettle_INCLUDE_DIR
+  Nettle_LIBRARY
+)
+
+# compatibility variables
+set(Nettle_VERSION_STRING ${Nettle_VERSION})