diff --git a/CHANGELOG.md b/CHANGELOG.md
index f7459b47..95510d63 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,18 @@
 Please see [CONTRIBUTING.md](https://github.com/cucumber/cucumber/blob/master/CONTRIBUTING.md) on how to contribute to Cucumber.
 
+## In Git
+
+### Added
+
+### Changed
+
+### Fixed
+
+* Statically linking `boost_system` ([#197](https://github.com/cucumber/cucumber-cpp/pull/197) Matthieu Longo)
+* Unable to `add_subdirectory(cucumber-cpp)` ([#211](https://github.com/cucumber/cucumber-cpp/pull/211) Sergey Bon)
+* Warning C4265 on Visual Studio ([#195](https://github.com/cucumber/cucumber-cpp/pull/195) Matthieu Longo)
+* Fix handling of optional regex captures ([#221](https://github.com/cucumber/cucumber-cpp/pull/221) Alain Martin)
+
 ## [0.5](https://github.com/cucumber/cucumber-cpp/compare/v0.4...v0.5) (2 July 2018)
 
 ### Added
diff --git a/CMakeLists.txt b/CMakeLists.txt
index df364be9..ca0d7115 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,23 +5,61 @@ if(NOT CMAKE_VERSION VERSION_LESS "3.3")
     cmake_policy(SET CMP0063 NEW)
 endif()
 
+if (NOT CMAKE_VERSION VERSION_LESS "3.13")
+    # CMP0077: option() honors normal variables
+    # https://cmake.org/cmake/help/latest/policy/CMP0077.html
+    cmake_policy(SET CMP0077 NEW)
+endif()
+
 project(Cucumber-Cpp)
 
 option(BUILD_SHARED_LIBS        "Generate shared libraries" OFF)
 option(CUKE_USE_STATIC_BOOST    "Statically link Boost (except boost::test)" ${WIN32})
 option(CUKE_USE_STATIC_GTEST    "Statically link Google Test" ON)
-option(CUKE_DISABLE_BOOST_TEST  "Disable boost:test" OFF)
-option(CUKE_DISABLE_GTEST       "Disable Google Test framework" OFF)
-option(CUKE_DISABLE_UNIT_TESTS  "Disable unit tests" OFF)
-option(CUKE_DISABLE_E2E_TESTS   "Disable end-to-end tests" OFF)
-option(CUKE_ENABLE_EXAMPLES     "Enable the examples" OFF)
-option(CUKE_DISABLE_QT          "Disable using Qt framework" OFF)
-option(VALGRIND_TESTS           "Run tests within Valgrind" OFF)
+option(CUKE_ENABLE_BOOST_TEST   "Enable Boost.Test framework" ON)
+option(CUKE_ENABLE_EXAMPLES     "Build examples" OFF)
+option(CUKE_ENABLE_GTEST        "Enable Google Test framework" ON)
+option(CUKE_ENABLE_QT           "Enable Qt framework" ON)
+option(CUKE_TESTS_E2E           "Enable end-to-end tests" ON)
+option(CUKE_TESTS_UNIT          "Enable unit tests" ON)
+option(CUKE_TESTS_VALGRIND      "Enable tests within Valgrind" OFF)
 set(GMOCK_SRC_DIR "" CACHE STRING "Google Mock framework sources path (otherwise downloaded)")
 set(GMOCK_VER "1.7.0" CACHE STRING "Google Mock framework version to be used")
 
 set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake/modules)
 
+#
+# Option deprecation: if deprecated option is defined
+# then print a warning and use its value instead
+#
+
+function(option_depr_message old prefer)
+    message (DEPRECATION "${old} is deprecated in favor of ${prefer}")
+endfunction()
+
+function(option_depr old prefer)
+    if(DEFINED ${old})
+        option_depr_message(${old} ${prefer})
+        set (${prefer} ${${old}} CACHE BOOL "Set from deprecated ${old}" FORCE)
+    endif()
+endfunction()
+
+function(option_depr_invert old prefer)
+    if(DEFINED ${old})
+        option_depr_message(${old} ${prefer})
+        set (${prefer} $<NOT:${${old}}> CACHE BOOL "Set from deprecated ${old}" FORCE)
+    endif()
+endfunction()
+
+
+option_depr_invert (CUKE_DISABLE_BOOST_TEST   CUKE_ENABLE_BOOST_TEST)
+option_depr_invert (CUKE_DISABLE_GTEST        CUKE_ENABLE_GTEST)
+option_depr_invert (CUKE_DISABLE_QT           CUKE_ENABLE_QT)
+option_depr_invert (CUKE_DISABLE_E2E_TESTS    CUKE_TESTS_E2E)
+option_depr_invert (CUKE_DISABLE_UNIT_TESTS   CUKE_TESTS_UNIT)
+option_depr        (VALGRIND_TESTS            CUKE_TESTS_VALGRIND)
+
+
 #
 # Generic Compiler Flags
 #
@@ -70,7 +108,7 @@ endif()
 
 set(Boost_USE_STATIC_RUNTIME OFF)
 set(CUKE_CORE_BOOST_LIBS thread system regex date_time program_options filesystem)
-if(NOT CUKE_DISABLE_BOOST_TEST)
+if(CUKE_ENABLE_BOOST_TEST)
     # "An external test runner utility is required to link with dynamic library" (Boost User's Guide)
     set(Boost_USE_STATIC_LIBS OFF)
     set(CMAKE_CXX_FLAGS "-DBOOST_TEST_DYN_LINK ${CMAKE_CXX_FLAGS}")
@@ -112,6 +150,11 @@ if(Boost_SYSTEM_LIBRARY AND NOT TARGET Boost::system)
         "IMPORTED_LOCATION" "${Boost_SYSTEM_LIBRARY}"
         "INTERFACE_LINK_LIBRARIES" "Boost::boost"
     )
+    if(Boost_USE_STATIC_LIBS)
+        set_target_properties(Boost::system PROPERTIES
+            "COMPILE_DEFINITIONS" BOOST_ERROR_CODE_HEADER_ONLY=1
+        )
+    endif()
 endif()
 if(Boost_FILESYSTEM_LIBRARY AND NOT TARGET Boost::filesystem)
     add_library(Boost::filesystem ${LIBRARY_TYPE} IMPORTED)
@@ -153,7 +196,7 @@ endif()
 # GTest
 #
 
-if(NOT CUKE_DISABLE_GTEST)
+if(CUKE_ENABLE_GTEST)
     set(GTEST_USE_STATIC_LIBS ${CUKE_USE_STATIC_GTEST})
     if(NOT GMOCK_ROOT)
         set(GMOCK_ROOT "${CMAKE_CURRENT_BINARY_DIR}/gmock")
@@ -165,7 +208,7 @@ endif()
 # Qt
 #
 
-if(NOT CUKE_DISABLE_QT)
+if(CUKE_ENABLE_QT)
     find_package(Qt5Core)
     find_package(Qt5Gui)
     find_package(Qt5Widgets)
@@ -205,7 +248,7 @@ endif()
 # Valgrind
 #
 
-if(VALGRIND_TESTS)
+if(CUKE_TESTS_VALGRIND)
     find_package(Valgrind REQUIRED)
     set(VALGRIND_ARGS --error-exitcode=2 --leak-check=full --undef-value-errors=no)
     if(NOT VALGRIND_VERSION_STRING VERSION_LESS 3.9)
@@ -260,14 +303,14 @@ add_subdirectory(src)
 # Tests
 #
 
-if(CUKE_DISABLE_UNIT_TESTS)
-    message(STATUS "Skipping unit tests")
-else()
+if(CUKE_TESTS_UNIT)
     enable_testing()
     add_subdirectory(tests)
+else()
+    message(STATUS "Skipping unit tests")
 endif()
 
-if(CUKE_DISABLE_E2E_TESTS)
+if(NOT CUKE_TESTS_E2E)
     message(STATUS "Skipping end-to-end tests")
 else()
     find_program(CUCUMBER_RUBY cucumber)
diff --git a/Gemfile b/Gemfile
index 6a6a0374..968f8493 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,5 +4,7 @@ group :test do
   gem 'cucumber', "=2.0.0"
   gem 'aruba', "=0.8.0"
   gem 'rspec', "=3.4.0"
+  gem 'childprocess', "=0.5.9"
+  gem 'ffi', "=1.9.25"
 end
 
diff --git a/README.md b/README.md
index e7614182..a6055350 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,10 @@ Cucumber-Cpp uses the wire protocol at the moment, so you will need
 Cucumber-Ruby installed and available on the path. It is also needed
 to run the functional test suite.
 
+Please mind that Cucumber-Cpp is not compatible with Cucumber-Ruby 3.x
+due to a [bug in its wire protocol](https://github.com/cucumber/cucumber-ruby/issues/1183)
+implementation.
+
 To install the Ruby prerequisites:
 
 ```
diff --git a/examples/CalcQt/CMakeLists.txt b/examples/CalcQt/CMakeLists.txt
index 1b3dd1a1..c09ec67c 100644
--- a/examples/CalcQt/CMakeLists.txt
+++ b/examples/CalcQt/CMakeLists.txt
@@ -15,10 +15,8 @@ if(TARGET Qt::Core AND TARGET Qt::Gui AND TARGET Qt::Widgets AND TARGET Qt::Test
     add_executable(calcqt src/CalcQt.cpp)
     target_link_libraries(calcqt PRIVATE libcalcqt Qt::Widgets)
 
-    if(Qt::Test)
-        add_executable(QtTestCalculatorQtSteps features/step_definitions/QtTestCalculatorQtSteps)
-        target_link_libraries(QtTestCalculatorQtSteps PRIVATE libcalcqt Qt::Test cucumber-cpp)
-    endif()
+    add_executable(QtTestCalculatorQtSteps features/step_definitions/QtTestCalculatorQtSteps)
+    target_link_libraries(QtTestCalculatorQtSteps PRIVATE libcalcqt Qt::Test cucumber-cpp)
 
     if(TARGET Boost::unit_test_framework)
         add_executable(BoostCalculatorQtSteps features/step_definitions/BoostCalculatorQtSteps.cpp)
diff --git a/include/cucumber-cpp/internal/hook/HookRegistrar.hpp b/include/cucumber-cpp/internal/hook/HookRegistrar.hpp
index 61d6a605..f46520d3 100644
--- a/include/cucumber-cpp/internal/hook/HookRegistrar.hpp
+++ b/include/cucumber-cpp/internal/hook/HookRegistrar.hpp
@@ -22,6 +22,8 @@ class CUCUMBER_CPP_EXPORT CallableStep {
 
 class CUCUMBER_CPP_EXPORT Hook {
 public:
+    virtual ~Hook() {}
+
     void setTags(const std::string &csvTagNotation);
     virtual void invokeHook(Scenario *scenario, CallableStep *step);
     virtual void skipHook();
diff --git a/include/cucumber-cpp/internal/step/StepManager.hpp b/include/cucumber-cpp/internal/step/StepManager.hpp
index 457ee899..e6e91f50 100644
--- a/include/cucumber-cpp/internal/step/StepManager.hpp
+++ b/include/cucumber-cpp/internal/step/StepManager.hpp
@@ -102,6 +102,9 @@ class CUCUMBER_CPP_EXPORT InvokeResult {
 class CUCUMBER_CPP_EXPORT StepInfo : public boost::enable_shared_from_this<StepInfo> {
 public:
     StepInfo(const std::string &stepMatcher, const std::string source);
+
+    virtual ~StepInfo() {}
+
     SingleStepMatch matches(const std::string &stepDescription) const;
     virtual InvokeResult invokeStep(const InvokeArgs * pArgs) const = 0;
 
@@ -115,6 +118,8 @@ class CUCUMBER_CPP_EXPORT StepInfo : public boost::enable_shared_from_this<StepI
 
 class CUCUMBER_CPP_EXPORT BasicStep {
 public:
+    virtual ~BasicStep() {}
+
     InvokeResult invoke(const InvokeArgs *pArgs);
 
 protected:
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 7e43a59b..024af47e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -72,7 +72,7 @@ foreach(TARGET
     target_include_directories(${TARGET}
         PUBLIC
             $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
-            $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/include>
+            $<BUILD_INTERFACE:${CUKE_INCLUDE_DIR}>
             $<INSTALL_INTERFACE:$<INSTALL_PREFIX>/include>
     )
     # Declaring json_spirit.header to be a direct dependency with target_link_libraries breaks installation
diff --git a/src/Regex.cpp b/src/Regex.cpp
index c67a4648..3ff47970 100644
--- a/src/Regex.cpp
+++ b/src/Regex.cpp
@@ -37,6 +37,8 @@ FindRegexMatch::FindRegexMatch(const boost::regex &regexImpl, const std::string
             if (i->matched) {
                 RegexSubmatch s = {*i, i->first - expression.begin()};
                 submatches.push_back(s);
+            } else {
+                submatches.push_back(RegexSubmatch());
             }
         }
     }
diff --git a/tests/unit/RegexTest.cpp b/tests/unit/RegexTest.cpp
index 8fa97d61..a618ba16 100644
--- a/tests/unit/RegexTest.cpp
+++ b/tests/unit/RegexTest.cpp
@@ -46,6 +46,22 @@ TEST(RegexTest, matchesRegexWithSubmatches) {
     EXPECT_EQ("69", match->getSubmatches()[1].value);
 }
 
+TEST(RegexTest, matchesRegexWithOptionalSubmatches) {
+    Regex sum("^(\\d+)\\+(\\d+)(?:\\+(\\d+))?=(\\d+)$");
+
+    shared_ptr<RegexMatch> match(sum.find("1+2+3=6"));
+    EXPECT_TRUE(match->matches());
+    ASSERT_EQ(4, match->getSubmatches().size());
+
+    match = shared_ptr<RegexMatch>(sum.find("42+27=69"));
+    EXPECT_TRUE(match->matches());
+    ASSERT_EQ(4, match->getSubmatches().size());
+    EXPECT_EQ("42", match->getSubmatches()[0].value);
+    EXPECT_EQ("27", match->getSubmatches()[1].value);
+    EXPECT_EQ("", match->getSubmatches()[2].value);
+    EXPECT_EQ("69", match->getSubmatches()[3].value);
+}
+
 TEST(RegexTest, findAllDoesNotMatchIfNoTokens) {
     Regex sum("([^,]+)(?:,|$)");
     shared_ptr<RegexMatch> match(sum.findAll(""));
diff --git a/travis.sh b/travis.sh
index 0a3ed509..ebfdf0bc 100755
--- a/travis.sh
+++ b/travis.sh
@@ -70,7 +70,9 @@ cmake --build build
 cmake --build build --target test
 cmake --build build --target features
 
-startXvfb # Start virtual X display server
+#
+# Execute Calc examples
+#
 
 for TEST in \
     build/examples/Calc/GTestCalculatorSteps \
@@ -78,20 +80,24 @@ for TEST in \
     build/examples/Calc/BoostCalculatorSteps \
     build/examples/Calc/FuncArgsCalculatorSteps \
 ; do
-    if [ -f "${TEST}" ]; then
-        "${TEST}" > /dev/null &
-        sleep 1
-        cucumber examples/Calc
-        wait %
-    fi
+    "${TEST}" > /dev/null &
+    sleep 1
+    cucumber examples/Calc
+    wait %
 done
 
+#
+# Execute QtCalc examples
+#
+
+startXvfb # Start virtual X display server
+
 for TEST in \
     build/examples/CalcQt/GTestCalculatorQtSteps \
     build/examples/CalcQt/QtTestCalculatorQtSteps \
     build/examples/CalcQt/BoostCalculatorQtSteps \
 ; do
-    if [ -f "${TEST}" -a -n "${DISPLAY:-}" ]; then
+    if [ -n "${DISPLAY:-}" ]; then
         "${TEST}" 2> /dev/null &
         sleep 1
         cucumber examples/CalcQt
@@ -99,16 +105,18 @@ for TEST in \
     fi
 done
 
-# Test unix sockets
+killXvfb
+
+#
+# Execute feature showcase on Unix socket
+#
+
 SOCK=cucumber.wire.sock
 TEST=build/examples/FeatureShowcase/FeatureShowcaseSteps
-if [ -f "${TEST}" ]; then
-    echo "unix: ${SOCK}" > examples/FeatureShowcase/features/step_definitions/cucumber.wire
-    "${TEST}" --unix "${SOCK}" > /dev/null &
-    cucumber examples/FeatureShowcase
-    wait %
-fi
+echo "unix: ${SOCK}" > examples/FeatureShowcase/features/step_definitions/cucumber.wire
+"${TEST}" --unix "${SOCK}" > /dev/null &
+cucumber examples/FeatureShowcase
+wait %
 
-killXvfb
 
 cmake --build build --target install