Update changelogs for v2.4.0 release

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

ChangeLog.md

@@ -7,8 +7,8 @@ All notable changes to the project are documented in this file.
 [v2.4.0][UNRELEASED]
 --------------------
 
-Please note, this release is a major ABI bump due to change in the
-`uev_t` which requires recompiling all programs that use libuEv.
+Please note, this release is a major ABI bump due to changes in `uev_t`
+which requires recompiling all programs that use libuEv.
 
 Also, libuEv is built for 64 bit `time_t`, this means all applications
 that link with libuEv also must be built with the same build flags.
@@ -17,16 +17,22 @@ require applications to add the following to their `CPPFLAGS`:
 
     CPPFLAGS += -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64
 
+Applications that use `pkg-config` will get these extra flags from the
+`libuev.pc` file in the distribution archive.
+
 
 ### Changes
+- More examples added for fork + signals + timer
 - Add `struct signalfd_siginfo` to `uev_t`, valid for signal watchers.
   Now more metadata is available to signal callbacks
 
 ### Fixes
+- Fix #24: Replace obsolete autotools macro, by Otto Urpelainen
 - Fix #25: GLIBC v2.34 require `-D_FILE_OFFSET_BITS=64` for applications
   and libraries that want a 64-bit `time_t`.  Affects library and test
   programs used for `make check`, as well as all other applications that
   link with libuEv, so the `libuev.pc` file is also updated
+- Fix error handling in callbacks in examples
 
 
 [v2.3.2][] - 2021-02-12