-AC_CHECK_FUNCS(getrusage times mkstemp strtof strtold snprintf ftruncate chsize)
-AC_CHECK_FUNCS(chdir strerror getlogin gethostname kill link symlink perror)
-AC_CHECK_FUNCS(sleep time ttyname signal alarm ctime clock access fork execl)
-AC_CHECK_FUNCS(wait setmode execvp pipe dup2 close fdopen strcasestr getrlimit)
-AC_CHECK_FUNCS(gettimeofday stat fstat lstat getpwuid vsnprintf dup getcwd)
-AC_CHECK_FUNCS(localtime_r gmtime_r strerror_r getpwuid_r)
-
-# Check for glibc backtrace functions
-AC_CHECK_FUNCS(backtrace backtrace_symbols)
-
-# Check for types
-AC_CHECK_TYPES([intptr_t])
-AC_CHECK_TYPES([uintptr_t])
-
-# Check libc for getgid, getpid, getuid
-AC_CHECK_LIB([c],[getgid],[AC_DEFINE([HAVE_GETGID],[1],[libc includes getgid])])
-AC_CHECK_LIB([c],[getpid],[AC_DEFINE([HAVE_GETPID],[1],[libc includes getpid])])
-AC_CHECK_LIB([c],[getppid],[AC_DEFINE([HAVE_GETPPID],[1],[libc includes getppid])])
-AC_CHECK_LIB([c],[getuid],[AC_DEFINE([HAVE_GETUID],[1],[libc includes getuid])])
-AC_CHECK_LIB([c],[geteuid],[AC_DEFINE([HAVE_GETEUID],[1],[libc includes geteuid])])
+AC_CHECK_FUNCS_ONCE(getrusage times mkstemp strtof strtold snprintf \
+ftruncate chsize chdir getlogin gethostname kill link symlink sleep ttyname \
+alarm access fork execl wait setmode execve pipe dup2 close \
+strcasestr getrlimit gettimeofday stat fstat lstat getpwuid vsnprintf dup \
+getcwd localtime_r gmtime_r strerror_r getpwuid_r ttyname_r clock_gettime \
+readlink getgid getpid getppid getuid geteuid)