Detect Regex lib with cmake instead of pkg_config

cmake/FindRegex.cmake

@@ -0,0 +1,48 @@
+# - Try to find the Regex library
+#
+# Once done this will define
+#
+#  REGEX_FOUND       - system has libregex
+#  REGEX_INCLUDE_DIR - the libregex include directory
+#  REGEX_LIBRARIES   - Link these to use libregex
+#
+# Copyright (c) 2018, Gilles Caulier, <caulier dot gilles at gmail dot com>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+
+find_path(Regex_INCLUDE_DIR
+          NAMES regex.h
+          DOC "libregex include directory"
+)
+
+mark_as_advanced(Regex_INCLUDE_DIR)
+
+find_library(Regex_LIBRARY "regex"
+             DOC "libregex libraries"
+)
+
+mark_as_advanced(Regex_LIBRARY)
+
+find_package_handle_standard_args(Regex
+                                  FOUND_VAR Regex_FOUND
+                                  REQUIRED_VARS Regex_INCLUDE_DIR
+                                  FAIL_MESSAGE "Failed to find libregex"
+)
+
+if(REGEX_FOUND)
+
+    set(REGEX_INCLUDE_DIRS ${Regex_INCLUDE_DIRS})
+
+    if(Regex_LIBRARY)
+
+        set(REGEX_LIBRARIES ${Regex_LIBRARY})
+
+    else()
+
+        unset(REGEX_LIBRARIES)
+
+    endif()
+
+endif()

cmake/findDependencies.cmake

@@ -11,8 +11,7 @@ endif()
 find_package(Threads REQUIRED)
 
 if(MINGW)
-    find_package(PkgConfig REQUIRED)
-    pkg_check_modules(REGEX REQUIRED regex)
+    find_package(Regex REQUIRED)
     if(REGEX_FOUND)
         include_directories(${REGEX_INCLUDE_DIRS})
     endif()