Add synchronous gauge. Closes #181

Author: duncanpo

CMakeLists.txt

@@ -195,6 +195,8 @@ if(NOT DEFINED OTEL_CPP_INSTALLED_DIR)
 
    set(OTEL_CPP_CXX_STANDARD 14)
 
+   set(OTEL_ABI_VERSION OPENTELEMETRY_ABI_VERSION_NO=2)
+
    set(PATCHES_DIR ${CMAKE_SOURCE_DIR}/patches)
    if(SKIP_OTEL_CPP_PATCH)
        set(patch_comand "")
@@ -366,7 +368,7 @@ if(WITH_OTLP_FILE)
     target_compile_definitions(${OPENTELEMETRY_PROXY_LIBRARY_NAME} PRIVATE WITH_OTLP_FILE)
 endif()
 
-target_compile_definitions(${OPENTELEMETRY_PROXY_LIBRARY_NAME} PRIVATE OPENTELEMETRY_ABI_VERSION_NO=2)
+target_compile_definitions(${OPENTELEMETRY_PROXY_LIBRARY_NAME} PRIVATE ${OTEL_ABI_VERSION})
 
 # pass in version number
 target_compile_definitions(${OPENTELEMETRY_PROXY_LIBRARY_NAME} PRIVATE OTEL_MATLAB_VERSION="${OTEL_MATLAB_VERSION}")

examples/context_propagation/CMakeLists.txt

@@ -8,6 +8,7 @@ if(NOT DEFINED OTEL_CPP_INSTALLED_DIR)
     add_dependencies(${CONTEXTPROP_EXAMPLE_CPP_TARGET} ${OTEL_CPP_PROJECT_NAME})
 endif()
 
+target_compile_definitions(${CONTEXTPROP_EXAMPLE_CPP_TARGET} PRIVATE ${OTEL_ABI_VERSION})
 target_include_directories(${CONTEXTPROP_EXAMPLE_CPP_TARGET} PRIVATE ${OTEL_CPP_PREFIX}/include)
 target_link_libraries(${CONTEXTPROP_EXAMPLE_CPP_TARGET} PRIVATE ${OPENTELEMETRY_PROXY_LINK_LIBRARIES})
 if(UNIX AND NOT APPLE AND NOT CYGWIN)

examples/webread/CMakeLists.txt

@@ -5,6 +5,7 @@ if(NOT DEFINED OTEL_CPP_INSTALLED_DIR)
     add_dependencies(${WEBREAD_EXAMPLE_TARGET} ${OTEL_CPP_PROJECT_NAME})
 endif()
 
+target_compile_definitions(${WEBREAD_EXAMPLE_TARGET} PRIVATE ${OTEL_ABI_VERSION})
 target_include_directories(${WEBREAD_EXAMPLE_TARGET} PRIVATE ${OTEL_CPP_PREFIX}/include)
 target_link_libraries(${WEBREAD_EXAMPLE_TARGET} PRIVATE ${OPENTELEMETRY_PROXY_LINK_LIBRARIES})
 if(UNIX AND NOT APPLE AND NOT CYGWIN)