Homogeneize CMake logs (#2587)

[skip ci]
diff --git a/cmake/Modules/LocalGTest.cmake b/cmake/Modules/LocalGTest.cmake
index 2512914..fc612fd 100644
--- a/cmake/Modules/LocalGTest.cmake
+++ b/cmake/Modules/LocalGTest.cmake
@@ -27,9 +27,9 @@
     if(EXISTS "${AVIF_SOURCE_DIR}/ext/googletest")
         message(STATUS "libavif(AVIF_GTEST=LOCAL): ext/googletest found; using as FetchContent SOURCE_DIR")
         set(FETCHCONTENT_SOURCE_DIR_GOOGLETEST "${AVIF_SOURCE_DIR}/ext/googletest")
-        message(CHECK_START "libavif(AVIF_GTEST): configuring googletest")
+        message(CHECK_START "libavif(AVIF_GTEST=LOCAL): configuring googletest")
     else()
-        message(CHECK_START "libavif(AVIF_GTEST): fetching and configuring googletest")
+        message(CHECK_START "libavif(AVIF_GTEST=LOCAL): fetching and configuring googletest")
     endif()
 
     FetchContent_Declare(
diff --git a/cmake/Modules/LocalLibXml2.cmake b/cmake/Modules/LocalLibXml2.cmake
index 40f6991..ed0e9db 100644
--- a/cmake/Modules/LocalLibXml2.cmake
+++ b/cmake/Modules/LocalLibXml2.cmake
@@ -12,9 +12,9 @@
     if(EXISTS "${AVIF_SOURCE_DIR}/ext/libxml2")
         message(STATUS "libavif(AVIF_LIBXML2=LOCAL): ext/libxml2 found; using as FetchContent SOURCE_DIR")
         set(FETCHCONTENT_SOURCE_DIR_LIBXML2 "${AVIF_SOURCE_DIR}/ext/libxml2")
-        message(CHECK_START "libavif(AVIF_LIBXML2): configuring libxml2")
+        message(CHECK_START "libavif(AVIF_LIBXML2=LOCAL): configuring libxml2")
     else()
-        message(CHECK_START "libavif(AVIF_LIBXML2): fetching and configuring libxml2")
+        message(CHECK_START "libavif(AVIF_LIBXML2=LOCAL): fetching and configuring libxml2")
     endif()
 
     set(LIBXML2_WITH_PYTHON OFF CACHE INTERNAL "-")
diff --git a/cmake/Modules/LocalLibargparse.cmake b/cmake/Modules/LocalLibargparse.cmake
index 99e5e27..486bc0b 100644
--- a/cmake/Modules/LocalLibargparse.cmake
+++ b/cmake/Modules/LocalLibargparse.cmake
@@ -5,18 +5,18 @@
 )
 
 if(EXISTS "${LIBARGPARSE_FILENAME}")
-    message(STATUS "libavif(AVIF_LIBARGPARSE): compiled library found at ${LIBARGPARSE_FILENAME}")
+    message(STATUS "libavif(AVIF_LIBARGPARSE=LOCAL): compiled library found at ${LIBARGPARSE_FILENAME}")
     add_library(libargparse STATIC IMPORTED GLOBAL)
     set_target_properties(libargparse PROPERTIES IMPORTED_LOCATION "${LIBARGPARSE_FILENAME}" AVIF_LOCAL ON)
     target_include_directories(libargparse INTERFACE "${AVIF_SOURCE_DIR}/ext/libargparse/src")
 else()
-    message(STATUS "libavif(AVIF_LIBARGPARSE): compiled library not found at ${LIBARGPARSE_FILENAME}; using FetchContent")
+    message(STATUS "libavif(AVIF_LIBARGPARSE=LOCAL): compiled library not found at ${LIBARGPARSE_FILENAME}; using FetchContent")
     if(EXISTS "${AVIF_SOURCE_DIR}/ext/libargparse")
-        message(STATUS "libavif(AVIF_LIBARGPARSE): ext/libargparse found; using as FetchContent SOURCE_DIR")
+        message(STATUS "libavif(AVIF_LIBARGPARSE=LOCAL): ext/libargparse found; using as FetchContent SOURCE_DIR")
         set(FETCHCONTENT_SOURCE_DIR_LIBARGPARSE "${AVIF_SOURCE_DIR}/ext/libargparse")
-        message(CHECK_START "libavif(AVIF_LIBARGPARSE): configuring libargparse")
+        message(CHECK_START "libavif(AVIF_LIBARGPARSE=LOCAL): configuring libargparse")
     else()
-        message(CHECK_START "libavif(AVIF_LIBARGPARSE): fetching and configuring libargparse")
+        message(CHECK_START "libavif(AVIF_LIBARGPARSE=LOCAL): fetching and configuring libargparse")
     endif()
 
     FetchContent_Declare(