Found the following significant warnings:
  Rserv.c:375:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:372:2: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:816:4: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:817:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:820:22: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:821:22: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:2088:7: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:2090:7: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:2150:17: warning: 'RSA_generate_key' is deprecated [-Wdeprecated-declarations]
  Rserv.c:2342:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:3351:4: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  Rserv.c:3358:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  oc.c:47:33: warning: 'RAND_pseudo_bytes' is deprecated [-Wdeprecated-declarations]
  ./Rserv.c:375:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:372:2: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:816:4: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:817:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:820:22: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:821:22: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:2088:7: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:2090:7: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:2150:17: warning: 'RSA_generate_key' is deprecated [-Wdeprecated-declarations]
  ./Rserv.c:2342:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:3351:4: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  ./Rserv.c:3358:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
  standalone.c:220:3: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
See '/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/Rserve.Rcheck/00install.out' for details.