thodg/libgit2

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f423b82..de7e53c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,7 +65,7 @@ OPTION(DEBUG_POOL			"Enable debug pool allocator"				OFF)
 OPTION(ENABLE_WERROR			"Enable compilation with -Werror"			OFF)
 OPTION(USE_BUNDLED_ZLIB    		"Use the bundled version of zlib"			OFF)
 OPTION(DEPRECATE_HARD			"Do not include deprecated functions in the library"	OFF)
-   SET(REGEX				"" CACHE STRING "Regular expression implementation. One of regcomp_l, pcre, regcomp, or builtin.")
+   SET(REGEX				"" CACHE STRING "Regular expression implementation. One of regcomp_l, pcre2, pcre, regcomp, or builtin.")
 
 IF (UNIX AND NOT APPLE)
 	OPTION(ENABLE_REPRODUCIBLE_BUILDS "Enable reproducible builds"				OFF)
diff --git a/cmake/Modules/FindPCRE2.cmake b/cmake/Modules/FindPCRE2.cmake
new file mode 100644
index 0000000..122f0e9
--- /dev/null
+++ b/cmake/Modules/FindPCRE2.cmake
@@ -0,0 +1,38 @@
+# Copyright (C) 2007-2009 LuaDist.
+# Created by Peter Kapec <kapecp@gmail.com>
+# Redistribution and use of this file is allowed according to the terms of the MIT license.
+# For details see the COPYRIGHT file distributed with LuaDist.
+#	Note:
+#		Searching headers and libraries is very simple and is NOT as powerful as scripts
+#		distributed with CMake, because LuaDist defines directories to search for.
+#		Everyone is encouraged to contact the author with improvements. Maybe this file
+#		becomes part of CMake distribution sometimes.
+
+# - Find pcre
+# Find the native PCRE2 headers and libraries.
+#
+# PCRE2_INCLUDE_DIRS	- where to find pcre.h, etc.
+# PCRE2_LIBRARIES	- List of libraries when using pcre.
+# PCRE2_FOUND	- True if pcre found.
+
+# Look for the header file.
+FIND_PATH(PCRE2_INCLUDE_DIR NAMES pcre2posix.h)
+
+# Look for the library.
+FIND_LIBRARY(PCRE2_LIBRARY NAMES pcre2-8)
+FIND_LIBRARY(PCRE2_POSIX_LIBRARY NAMES pcre2-posix)
+
+# Handle the QUIETLY and REQUIRED arguments and set PCRE2_FOUND to TRUE if all listed variables are TRUE.
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(PCRE2 DEFAULT_MSG PCRE2_LIBRARY PCRE2_POSIX_LIBRARY PCRE2_INCLUDE_DIR)
+
+# Copy the results to the output variables.
+IF(PCRE2_FOUND)
+	SET(PCRE2_LIBRARIES ${PCRE2_LIBRARY} ${PCRE2_POSIX_LIBRARY})
+	SET(PCRE2_INCLUDE_DIRS ${PCRE2_INCLUDE_DIR})
+ELSE(PCRE2_FOUND)
+	SET(PCRE2_LIBRARIES)
+	SET(PCRE2_INCLUDE_DIRS)
+ENDIF(PCRE2_FOUND)
+
+MARK_AS_ADVANCED(PCRE2_INCLUDE_DIRS PCRE2_LIBRARIES)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 852a2af..cd4c688 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -307,6 +307,18 @@ ENDIF()
 IF(REGEX STREQUAL "regcomp_l")
 	ADD_FEATURE_INFO(regex ON "using system regcomp_l")
 	SET(GIT_REGEX_REGCOMP_L 1)
+ELSEIF(REGEX STREQUAL "pcre2")
+	FIND_PACKAGE(PCRE2)
+
+	IF(NOT PCRE2_FOUND)
+		MESSAGE(FATAL_ERROR "PCRE2 support was requested but not found")
+	ENDIF()
+
+	ADD_FEATURE_INFO(regex ON "using system PCRE2")
+	SET(GIT_REGEX_PCRE2 1)
+
+	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${PCRE2_INCLUDE_DIRS})
+	LIST(APPEND LIBGIT2_LIBS ${PCRE2_LIBRARIES})
 ELSEIF(REGEX STREQUAL "pcre")
 	ADD_FEATURE_INFO(regex ON "using system PCRE")
 	SET(GIT_REGEX_PCRE 1)
diff --git a/src/features.h.in b/src/features.h.in
index 5468cee..4090fad 100644
--- a/src/features.h.in
+++ b/src/features.h.in
@@ -19,6 +19,7 @@
 #cmakedefine GIT_REGEX_REGCOMP_L
 #cmakedefine GIT_REGEX_REGCOMP
 #cmakedefine GIT_REGEX_PCRE
+#cmakedefine GIT_REGEX_PCRE2
 #cmakedefine GIT_REGEX_BUILTIN 1
 
 #cmakedefine GIT_SSH 1
diff --git a/src/posix_regex.h b/src/posix_regex.h
index e76f69c..421ffeb 100644
--- a/src/posix_regex.h
+++ b/src/posix_regex.h
@@ -37,7 +37,9 @@
 
 #else
 
-# ifdef GIT_REGEX_PCRE
+# if defined(GIT_REGEX_PCRE2)
+#  include <pcre2posix.h>
+# elif defined(GIT_REGEX_PCRE)
 #  include <pcreposix.h>
 # else
 #  include <regex.h>