Provide CompactReporter declaration with EXTERNAL_INTERFACES

Related to #991
diff --git a/CMakeLists.txt b/CMakeLists.txt
index de1972a..3fb58ef 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -247,6 +247,7 @@
 set(REPORTER_HEADERS
         ${HEADER_DIR}/reporters/catch_reporter_automake.hpp
         ${HEADER_DIR}/reporters/catch_reporter_bases.hpp
+        ${HEADER_DIR}/reporters/catch_reporter_compact.h
         ${HEADER_DIR}/reporters/catch_reporter_multi.h
         ${HEADER_DIR}/reporters/catch_reporter_tap.hpp
         ${HEADER_DIR}/reporters/catch_reporter_teamcity.hpp