More portability issues. Sigaction is a symbol

Source/CTest/Curl/CMakeLists.txt

@@ -118,6 +118,7 @@ ENDIF(HAVE_LIBSSL)
 CHECK_LIBRARY_EXISTS("${CURL_LIBS}" dlopen "" HAVE_DLOPEN)
 
 SET(CMAKE_REQUIRED_LIBRARIES ${CURL_LIBS})
+CHECK_INCLUDE_FILE("features.h"       HAVE_FEATURES_H)
 CHECK_INCLUDE_FILE("sys/types.h"      HAVE_SYS_TYPES_H)
 CHECK_INCLUDE_FILE("inttypes.h"       HAVE_INTTYPES_H)
 CHECK_INCLUDE_FILE("alloca.h"         HAVE_ALLOCA_H)
@@ -216,10 +217,13 @@ CHECK_FUNCTION_EXISTS(tcgetattr         HAVE_TCGETATTR)
 CHECK_FUNCTION_EXISTS(perror            HAVE_PERROR)
 CHECK_FUNCTION_EXISTS(closesocket       HAVE_CLOSESOCKET)
 CHECK_FUNCTION_EXISTS(setvbuf           HAVE_SETVBUF)
-CHECK_FUNCTION_EXISTS(sigaction         HAVE_SIGACTION)
 CHECK_FUNCTION_EXISTS(signal            HAVE_SIGNAL)
 CHECK_FUNCTION_EXISTS(sigsetjmp         HAVE_SIGSETJMP)
 
+IF(HAVE_SIGNAL)
+  CHECK_SYMBOL_EXISTS(sigaction "signal.h" HAVE_SIGACTION)
+ENDIF(HAVE_SIGNAL)
+
 IF(NOT HAVE_SIGSETJMP)
   IF(HAVE_SETJMP_H)
     CHECK_SYMBOL_EXISTS(sigsetjmp "setjmp.h" HAVE_MACRO_SIGSETJMP)