build: remove check for gettimeofday & librt

Author: fanquake

configure.ac

@@ -919,8 +919,6 @@ if test "$ac_cv_sys_large_files" != "" &&
   CORE_CPPFLAGS="$CORE_CPPFLAGS -D_LARGE_FILES=$ac_cv_sys_large_files"
 fi
 
-AC_SEARCH_LIBS([clock_gettime],[rt])
-
 if test "$enable_gprof" = "yes"; then
     dnl -pg is incompatible with -pie. Since hardening and profiling together doesn't make sense,
     dnl we simply make them mutually exclusive here. Additionally, hardened toolchains may force