modify cmake to build nc

- modify structure of CMakeLists.txt under apps/
  * move apps/CMakeLists.txt to apps/openssl/ since this is for openssl build
  * create new apps/nc/CMakeLists.txt for nc build
  * modify apps/CMakeLists.txt just add_subdirectory()

- add checking and compile of arc4random_uniform()

- add installing man files, openssl.1 and nc.1

apps/nc/CMakeLists.txt

@@ -0,0 +1,54 @@
+if(BUILD_NC)
+
+include_directories(
+	.
+	./compat
+	../../include
+	../../include/compat
+)
+
+set(
+	NC_SRC
+	atomicio.c
+	netcat.c
+	socks.c
+	compat/socket.c
+)
+
+check_function_exists(b64_ntop HAVE_B64_NTOP)
+if(HAVE_B64_NTOP)
+	add_definitions(-DHAVE_B64_NTOP)
+else()
+	set(NC_SRC ${NC_SRC} compat/base64.c)
+endif()
+
+check_function_exists(accept4 HAVE_ACCEPT4)
+if(HAVE_ACCEPT4)
+	add_definitions(-DHAVE_ACCEPT4)
+else()
+	set(NC_SRC ${NC_SRC} compat/accept4.c)
+endif()
+
+check_function_exists(readpassphrase HAVE_READPASSPHRASE)
+if(HAVE_READPASSPHRASE)
+	add_definitions(-DHAVE_READPASSPHRASE)
+else()
+	set(NC_SRC ${NC_SRC} compat/readpassphrase.c)
+endif()
+
+check_function_exists(strtonum HAVE_STRTONUM)
+if(HAVE_STRTONUM)
+	add_definitions(-DHAVE_STRTONUM)
+else()
+	set(NC_SRC ${NC_SRC} compat/strtonum.c)
+endif()
+
+add_executable(nc ${NC_SRC})
+target_link_libraries(nc tls ${OPENSSL_LIBS})
+
+if(ENABLE_NC)
+	install(TARGETS nc DESTINATION bin)
+	install(FILES nc.1 DESTINATION share/man/man1)
+endif()
+
+endif()