build: check libev version

Signed-off-by: hexian000 <hexian000@outlook.com>

src/CMakeLists.txt

@@ -44,8 +44,16 @@ if(BUILD_STATIC OR LINK_STATIC_LIBS)
 else()
     find_library(LIBEV_LIBRARY NAMES ev)
 endif()
-if((NOT EXISTS ${LIBEV_INCLUDE_DIR}) OR (NOT EXISTS ${LIBEV_LIBRARY}))
-    message(FATAL_ERROR "libev not found")
+if(EXISTS "${LIBEV_INCLUDE_DIR}/ev.h")
+    file(READ "${LIBEV_INCLUDE_DIR}/ev.h" LIBEV_VERSION_STR)
+    string(REGEX MATCH "#define EV_VERSION_MAJOR[ \t]+([0-9]+)" _ ${LIBEV_VERSION_STR})
+    set(EV_VERSION_MAJOR ${CMAKE_MATCH_1})
+    string(REGEX MATCH "#define EV_VERSION_MINOR[ \t]+([0-9]+)" _ ${LIBEV_VERSION_STR})
+    set(EV_VERSION_MINOR ${CMAKE_MATCH_1})
+    set(LIBEV_VERSION "${EV_VERSION_MAJOR}.${EV_VERSION_MINOR}")
+endif()
+if((NOT ${LIBEV_VERSION} VERSION_GREATER_EQUAL "4.31") OR (NOT EXISTS ${LIBEV_LIBRARY}))
+    message(FATAL_ERROR "libev (>= 4.31) not found")
 endif()
 message(STATUS "libev: ${LIBEV_LIBRARY}")
 target_include_directories(kcptun-libev SYSTEM PRIVATE ${LIBEV_INCLUDE_DIR})

src/sockutil.h

@@ -40,9 +40,10 @@ bool sa_equals(const struct sockaddr *a, const struct sockaddr *b);
 bool sa_matches(const struct sockaddr *bind, const struct sockaddr *dest);
 int format_sa(const struct sockaddr *sa, char *buf, size_t buf_size);
 
-enum { RESOLVE_TCP = 0x0,
-       RESOLVE_UDP = 0x1,
-       RESOLVE_PASSIVE = 0x2,
+enum {
+	RESOLVE_TCP = 0x0,
+	RESOLVE_UDP = 0x1,
+	RESOLVE_PASSIVE = 0x2,
 };
 bool resolve_addr(union sockaddr_max *sa, const char *s, int flags);