Fixed --test-build-*.

Fixes various aspects of --test-build-devpoll, --test-build-eventport, and
--test-build-epoll.

In particular, if --test-build-devpoll was used on Linux, then "devpoll"
event method would be preferred over "epoll".  Also, wrong definitions of
event macros were chosen.

src/event/ngx_event.c

diff --git a/src/event/ngx_event.c b/src/event/ngx_event.c
index 77800b7..38f9b38 100644
--- a/src/event/ngx_event.c
+++ b/src/event/ngx_event.c
@@ -1208,7 +1208,7 @@
 
 #endif
 
-#if (NGX_HAVE_DEVPOLL)
+#if (NGX_HAVE_DEVPOLL) && !(NGX_TEST_BUILD_DEVPOLL)
 
     module = &ngx_devpoll_module;
 

src/event/ngx_event.h

diff --git a/src/event/ngx_event.h b/src/event/ngx_event.h
index 03854d8..591005a 100644
--- a/src/event/ngx_event.h
+++ b/src/event/ngx_event.h
@@ -343,7 +343,8 @@
 #define NGX_DISABLE_EVENT  EV_DISABLE
 
 
-#elif (NGX_HAVE_DEVPOLL || NGX_HAVE_EVENTPORT)
+#elif (NGX_HAVE_DEVPOLL && !(NGX_TEST_BUILD_DEVPOLL)) \
+      || (NGX_HAVE_EVENTPORT && !(NGX_TEST_BUILD_EVENTPORT))
 
 #define NGX_READ_EVENT     POLLIN
 #define NGX_WRITE_EVENT    POLLOUT
@@ -352,7 +353,7 @@
 #define NGX_ONESHOT_EVENT  1
 
 
-#elif (NGX_HAVE_EPOLL)
+#elif (NGX_HAVE_EPOLL) && !(NGX_TEST_BUILD_EPOLL)
 
 #define NGX_READ_EVENT     (EPOLLIN|EPOLLRDHUP)
 #define NGX_WRITE_EVENT    EPOLLOUT

src/os/unix/ngx_posix_config.h

diff --git a/src/os/unix/ngx_posix_config.h b/src/os/unix/ngx_posix_config.h
index bf75997..5d1358e 100644
--- a/src/os/unix/ngx_posix_config.h
+++ b/src/os/unix/ngx_posix_config.h
@@ -128,7 +128,7 @@
 #endif
 
 
-#if (NGX_HAVE_DEVPOLL)
+#if (NGX_HAVE_DEVPOLL) && !(NGX_TEST_BUILD_DEVPOLL)
 #include <sys/ioctl.h>
 #include <sys/devpoll.h>
 #endif