Updates cmake setup for reducing sources of version info.

Addresses #372: Multiple sources of project's version.

Build/xcode5/PlayRho.xcodeproj/project.pbxproj

@@ -396,6 +396,8 @@
 		4706451C25336237006E69AA /* LimitState.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = LimitState.hpp; sourceTree = "<group>"; };
 		4706451E25336323006E69AA /* LimitState.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = LimitState.cpp; sourceTree = "<group>"; };
 		470ADAAB25546D2700EEE99D /* ArrayAllocator.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = ArrayAllocator.cpp; sourceTree = "<group>"; };
+		470ADAB82555E05100EEE99D /* Defines.hpp.in */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = Defines.hpp.in; sourceTree = "<group>"; };
+		470ADAB92555F72B00EEE99D /* Real.hpp.in */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = Real.hpp.in; sourceTree = "<group>"; };
 		470D533C1E82364F00E96896 /* SpinningCircle.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = SpinningCircle.hpp; sourceTree = "<group>"; };
 		470F94A51EC4C79B00AA3C82 /* BodyConf.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = BodyConf.hpp; sourceTree = "<group>"; };
 		470F94AB1EC4CAE600AA3C82 /* FixtureConf.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = FixtureConf.hpp; sourceTree = "<group>"; };
@@ -637,7 +639,6 @@
 		47B58F5F1F5B791500354C34 /* FlagGuard.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = FlagGuard.cpp; sourceTree = "<group>"; };
 		47B58F621F64C19600354C34 /* RealConstants.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = RealConstants.hpp; sourceTree = "<group>"; };
 		47B58F651F64D2B500354C34 /* Real.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Real.hpp; sourceTree = "<group>"; };
-		47B58F671F64D2D200354C34 /* Real.hpp.in */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = Real.hpp.in; sourceTree = "<group>"; };
 		47BE7FE125390E8F00CF0F22 /* BodyType.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = BodyType.cpp; sourceTree = "<group>"; };
 		47C85D091EFA251B00F70C56 /* WheelJoint.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = WheelJoint.cpp; sourceTree = "<group>"; };
 		47C85D0B1EFA2C1C00F70C56 /* Version.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Version.cpp; sourceTree = "<group>"; };
@@ -943,6 +944,7 @@
 			children = (
 				80BB8923141C3E5900F1753A /* PlayRho.hpp */,
 				47327E7D1EA585790048FCD8 /* Defines.hpp */,
+				470ADAB82555E05100EEE99D /* Defines.hpp.in */,
 				80BB8926141C3E5900F1753A /* Collision */,
 				80BB893E141C3E5900F1753A /* Common */,
 				80BB894C141C3E5900F1753A /* Dynamics */,
@@ -1045,7 +1047,7 @@
 				4764085E2507FBFF0090F711 /* propagate_const.hpp */,
 				470F94E01ECBB3A100AA3C82 /* Range.hpp */,
 				47B58F651F64D2B500354C34 /* Real.hpp */,
-				47B58F671F64D2D200354C34 /* Real.hpp.in */,
+				470ADAB92555F72B00EEE99D /* Real.hpp.in */,
 				47B58F621F64C19600354C34 /* RealConstants.hpp */,
 				80BB8947141C3E5900F1753A /* Settings.hpp */,
 				4734B21E1DC1340500F15E29 /* Span.hpp */,

CMakeLists.txt

@@ -1,12 +1,44 @@
 # This is a configuration file for CMake.
-# Top level docs for 3.1.3 at: https://cmake.org/cmake/help/v3.1/
-# Commands herein described at: https://cmake.org/cmake/help/v3.1/manual/cmake-commands.7.html
+# Commands herein described at: https://cmake.org/cmake/help/latest/manual/cmake-commands.7.html
 
 # Minimally require a CMake version that can handle what's necessary...
 # According to the following link, support for cxx_std_17 first became available in CMake 3.8.
 # https://github.com/Kitware/CMake/blob/07cfb18f9d29cfc0588ede928846a03ec5599c48/Help/release/3.8.rst
-# It's not clear that CMake 3.8 is enough though. So 3.10 is picked in hopes that dust settled then.
-cmake_minimum_required(VERSION 3.10)
+# Availability of CMAKE_PROJECT_VERSION first appeared in CMake 3.12
+cmake_minimum_required(VERSION 3.12)
+
+foreach(p
+    CMP0048 # OK to clear PROJECT_VERSION on project()
+    CMP0054 # CMake 3.1
+    CMP0056 # export EXE_LINKER_FLAGS to try_run
+    CMP0057 # Support no if() IN_LIST operator
+    CMP0063 # Honor visibility properties for all targets
+    CMP0077 # Allow option() overrides in importing projects
+    )
+  if(POLICY ${p})
+    cmake_policy(SET ${p} NEW)
+  endif()
+endforeach()
+
+# Set name for entire project. This establishes the project name in <PROJECT_NAME>_* variables.
+# Details at: https://cmake.org/cmake/help/latest/command/project.html#command:project
+project(PlayRho VERSION 0.12.1)
+# Now PlayRho_VERSION set to version above.
+# PlayRho_VERSION_MAJOR set to first component.
+# PlayRho_VERSION_MINOR set to second component.
+# PlayRho_VERSION_PATCH set to third component.
+set(PLAYRHO_VERSION PlayRho_VERSION)
+
+# Make sure we can import our CMake functions
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+
+# Read the git tags to determine the project version
+include(GetGitVersion)
+get_git_version(GIT_VERSION)
+
+# Tell the user what versions we are using
+string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+" VERSION ${GIT_VERSION})
+message(STATUS "Version: ${VERSION}")
 
 # Require C++17...
 set(CMAKE_CXX_STANDARD 17)
@@ -22,10 +54,6 @@ endif()
 # else will be ignored. PlayRho only supports Debug and Release
 set(CMAKE_CONFIGURATION_TYPES "Debug;Release;" CACHE STRING "Semicolon separated list of supported configuration types. PlayRho only supports Debug and Release configurations.")
 
-# Set name for entire project.
-# Details at: https://cmake.org/cmake/help/v3.1/command/project.html
-project(PlayRho)
-
 # Tell C++ compiler to optimize release builds for speed.
 # In clang++, the optimize for speed flag is '-Ot'. This option isn't supported on g++
 # however and it'd be nice to use an option that works for both compilers. So use '-O3'.
@@ -49,7 +77,6 @@ option(PLAYRHO_BUILD_BENCHMARK "Build PlayRho Benchmark console application." OF
 option(PLAYRHO_BUILD_TESTBED "Build PlayRho Testbed GUI application." OFF)
 option(PLAYRHO_ENABLE_COVERAGE "Enable code coverage generation." OFF)
 
-set(PLAYRHO_VERSION 0.12.0)
 set(LIB_INSTALL_DIR lib${LIB_SUFFIX})
 
 # Tell Microsoft Visual C (MSVC) to enable unwind semantics since it doesn't by default.
@@ -94,5 +121,8 @@ if(PLAYRHO_BUILD_BENCHMARK)
 endif(PLAYRHO_BUILD_BENCHMARK)
 
 if(PLAYRHO_INSTALL_DOC)
-  install(DIRECTORY Documentation DESTINATION share/doc/PlayRho PATTERN ".svn" EXCLUDE)
+  find_package(Doxygen)
+  if (DOXYGEN_FOUND)
+    add_subdirectory(Documentation)
+  endif()
 endif(PLAYRHO_INSTALL_DOC)

Documentation/CMakeLists.txt

@@ -0,0 +1,10 @@
+configure_file(Doxyfile.in Doxyfile @ONLY)
+
+add_custom_target(Documentation ALL "${DOXYGEN_EXECUTABLE}"
+  WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/Documentation"
+  COMMENT "Generating HTML documentation" VERBATIM)
+
+install(
+  DIRECTORY "${CMAKE_BINARY_DIR}/Documentation/html"
+  DESTINATION "${CMAKE_INSTALL_DOCDIR}"
+)

Documentation/Doxyfile

@@ -38,7 +38,7 @@ PROJECT_NAME           = PlayRho
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 0.12.0
+PROJECT_NUMBER         = $(PLAYRHO_VERSION)
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a