CLEANUP: build: rename some build macros to use the USE_* ones

We still have quite a number of build macros which are mapped 1:1 to a
USE_something setting in the makefile but which have a different name.
This patch cleans this up by renaming them to use the USE_something
one, allowing to clean up the makefile and make it more obvious when
reading the code what build option needs to be added.

The following renames were done :

 ENABLE_POLL -> USE_POLL
 ENABLE_EPOLL -> USE_EPOLL
 ENABLE_KQUEUE -> USE_KQUEUE
 ENABLE_EVPORTS -> USE_EVPORTS
 TPROXY -> USE_TPROXY
 NETFILTER -> USE_NETFILTER
 NEED_CRYPT_H -> USE_CRYPT_H
 CONFIG_HAP_CRYPT -> USE_LIBCRYPT
 CONFIG_HAP_NS -> DUSE_NS
 CONFIG_HAP_LINUX_SPLICE -> USE_LINUX_SPLICE
 CONFIG_HAP_LINUX_TPROXY -> USE_LINUX_TPROXY
 CONFIG_HAP_LINUX_VSYSCALL -> USE_LINUX_VSYSCALL
diff --git a/include/common/epoll.h b/include/common/epoll.h
index cc395cd..f45aa4f 100644
--- a/include/common/epoll.h
+++ b/include/common/epoll.h
@@ -29,7 +29,7 @@
 #ifndef _COMMON_EPOLL_H
 #define _COMMON_EPOLL_H
 
-#if defined (__linux__) && defined(ENABLE_EPOLL)
+#if defined (__linux__) && defined(USE_EPOLL)
 
 #ifndef USE_MY_EPOLL
 #include <sys/epoll.h>
@@ -70,7 +70,7 @@
 	} data;
 };
 
-#if defined(CONFIG_HAP_LINUX_VSYSCALL) && defined(__linux__) && defined(__i386__)
+#if defined(USE_LINUX_VSYSCALL) && defined(__linux__) && defined(__i386__)
 /* Those are our self-defined functions */
 extern int epoll_create(int size);
 extern int epoll_ctl(int epfd, int op, int fd, struct epoll_event * event);
@@ -94,7 +94,7 @@
 
 #endif /* USE_MY_EPOLL */
 
-#endif /* __linux__ && ENABLE_EPOLL */
+#endif /* __linux__ && USE_EPOLL */
 
 #endif /* _COMMON_EPOLL_H */