build: remove Boost Chrono detection from build system

Author: fanquake

build-aux/m4/ax_boost_chrono.m4

@@ -47,9 +47,6 @@
 /* define if the Boost library is available */
 #define HAVE_BOOST /**/
 
-/* define if the Boost::Chrono library is available */
-#define HAVE_BOOST_CHRONO /**/
-
 /* define if the Boost::Filesystem library is available */
 #define HAVE_BOOST_FILESYSTEM /**/
 

build_msvc/bitcoin_config.h

@@ -1139,7 +1139,6 @@ fi
 AX_BOOST_SYSTEM
 AX_BOOST_FILESYSTEM
 AX_BOOST_THREAD
-AX_BOOST_CHRONO
 
 dnl Boost 1.56 through 1.62 allow using std::atomic instead of its own atomic
 dnl counter implementations. In 1.63 and later the std::atomic approach is default.
@@ -1206,7 +1205,7 @@ fi
 
 if test x$use_boost = xyes; then
 
-BOOST_LIBS="$BOOST_LDFLAGS $BOOST_SYSTEM_LIB $BOOST_FILESYSTEM_LIB $BOOST_THREAD_LIB $BOOST_CHRONO_LIB"
+BOOST_LIBS="$BOOST_LDFLAGS $BOOST_SYSTEM_LIB $BOOST_FILESYSTEM_LIB $BOOST_THREAD_LIB"
 
 
 dnl If boost (prior to 1.57) was built without c++11, it emulated scoped enums