iox-#2099 Skip the introspection build if the curses library is not f…

…ound (e.g. ROS 2 RHEL)

tools/introspection/CMakeLists.txt

@@ -44,7 +44,11 @@ endif()
 # cmake doesn't find ncurses under QNX; let the compiler complain if the header is missing
 if(NOT QNX)
     SET(CURSES_USE_NCURSES TRUE)
-    find_package(Curses REQUIRED)
+    find_package(Curses QUIET)
+    if(NOT CURSES_FOUND)
+        message(STATUS "The build of the introspection client is skipped due to missing the curses library")
+        return()
+    endif()
     if(${CURSES_HAVE_NCURSES_H} MATCHES ".*-NOTFOUND")
         message(SEND_ERROR "ncurses header not found! Please install libncurses5-dev!")
     endif(${CURSES_HAVE_NCURSES_H} MATCHES ".*-NOTFOUND")