configure.ac: improve error message

diff --git a/configure.ac b/configure.ac
index 73e95bb8bacc55458cf01762840840f925f5e5be..8a3974ff65cc953b8e00650b01b0dd7be9e73201 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -55,7 +55,8 @@ AC_CHECK_FUNCS([gettimeofday munmap socket strerror strtol])
 # URCU
 
 # urcu - check if we just find the headers it out of the box.
-AC_CHECK_HEADERS([urcu-bp.h], [], [AC_MSG_ERROR([Cannot find [URCU] headers (urcu-bp.h). Use [CFLAGS]=-Idir to specify their location.])])
+AC_CHECK_HEADERS([urcu-bp.h], [], [AC_MSG_ERROR([Cannot find [URCU] headers (urcu-bp.h). Use [CFLAGS]=-Idir to specify their location.
+This error can also occur when the liburcu package's configure script has not been run.])])
 
 # urcu - check that URCU lib is available to compilation
 AC_CHECK_LIB([urcu-bp], [synchronize_rcu], [], [AC_MSG_ERROR([Cannot find liburcu-bp lib. Use [LDFLAGS]=-Ldir to specify its location.])])