Define KUZU_VERSION as an extern global

Since it's set using a compile definition, we want to avoid that definition being required to include the header

src/common/CMakeLists.txt

@@ -10,6 +10,7 @@ add_subdirectory(vector)
 
 add_library(kuzu_common
         OBJECT
+        constants.cpp
         expression_type.cpp
         file_utils.cpp
         in_mem_overflow_buffer.cpp

src/common/constants.cpp

@@ -0,0 +1,6 @@
+namespace kuzu {
+namespace common {
+
+const char* KUZU_VERSION = KUZU_CMAKE_VERSION;
+}
+} // namespace kuzu

src/include/common/constants.h

@@ -5,7 +5,7 @@
 namespace kuzu {
 namespace common {
 
-constexpr char KUZU_VERSION[] = KUZU_CMAKE_VERSION;
+extern const char* KUZU_VERSION;
 
 constexpr uint64_t DEFAULT_VECTOR_CAPACITY_LOG_2 = 11;
 constexpr uint64_t DEFAULT_VECTOR_CAPACITY = (uint64_t)1 << DEFAULT_VECTOR_CAPACITY_LOG_2;