Fix version numbering in CMakeLists.txt

Fixes #115. Read the version number out of `cxxopts.hpp` instead of
having to duplicate it in CMakeLists.txt.

CHANGELOG.md

@@ -12,6 +12,7 @@ options. The project adheres to semantic versioning.
 ### Bug Fixes
 
 * Fix a warning about possible loss of data.
+* Fix version numbering in CMakeLists.txt
 
 ## 2.1.1
 

CMakeLists.txt

@@ -22,7 +22,16 @@ project(cxxopts)
 
 enable_testing()
 
-set(VERSION "1.2.0")
+file(STRINGS "${PROJECT_SOURCE_DIR}/include/cxxopts.hpp" cxxopts_version_defines
+     REGEX "#define {CXXOPTS__VERSION_(MAJOR|MINOR|PATCH)")
+foreach(ver ${cxxopts_version_defines})
+    if(ver MATCHES "#define {CXXOPTS__VERSION_(MAJOR|MINOR|PATCH) +([^ ]+)$")
+        set({CXXOPTS__VERSION_${CMAKE_MATCH_1} "${CMAKE_MATCH_2}" CACHE INTERNAL "")
+    endif()
+endforeach()
+set(VERSION ${CXXOPTS__VERSION_MAJOR}.${CXXOPTS__VERSION_MINOR}.${CXXOPTS__VERSION_PATCH})
+
+# set(VERSION "1.2.0")
 
 option(CXXOPTS_BUILD_EXAMPLES "Set to ON to build examples" ON)
 option(CXXOPTS_BUILD_TESTS "Set to ON to build tests" OFF)

include/cxxopts.hpp

@@ -43,11 +43,19 @@ THE SOFTWARE.
 #define CXXOPTS_HAS_OPTIONAL
 #endif
 
+#define CXXOPTS__VERSION_MAJOR 2
+#define CXXOPTS__VERSION_MINOR 2
+#define CXXOPTS__VERSION_PATCH 0
+
 namespace cxxopts
 {
   static constexpr struct {
     uint8_t major, minor, patch;
-  } version = {2, 1, 0};
+  } version = {
+    CXXOPTS__VERSION_MAJOR,
+    CXXOPTS__VERSION_MINOR,
+    CXXOPTS__VERSION_PATCH
+  };
 }
 
 //when we ask cxxopts to use Unicode, help strings are processed using ICU,