configure.ac: fix FTBFS with new glibc

glibc moved clock_* functions from librt to the core libc. As a result,
clock_gettime is no more a suitable symbol to use when finding librt.
Look for mq_open instead.
Reference:
http://www.sourceware.org/git/gitweb.cgi?p=glibc.git&h=6e6249d0b461b952d0f544792372663feb6d792a

Fixes a FTBFS in Fedora Rawhide.

diff --git a/configure.ac b/configure.ac
index c4638d15a18a387ded5534f4894ddc5663005eb8..71ea6ad25baab7bc432befab951cb897c88df649 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -171,7 +171,7 @@ CC_CHECK_FLAGS_APPEND([with_ldflags], [LDFLAGS], [\
         -Wl,-z,now])
 AC_SUBST([OUR_LDFLAGS], $with_ldflags)
 
-AC_SEARCH_LIBS([clock_gettime], [rt], [], [AC_MSG_ERROR([*** POSIX RT library not found])])
+AC_SEARCH_LIBS([mq_open], [rt], [], [AC_MSG_ERROR([*** POSIX RT library not found])])
 AC_SEARCH_LIBS([dlsym], [dl], [], [AC_MSG_ERROR([*** Dynamic linking loader library not found])])
 
 save_LIBS="$LIBS"