Fix: re-enable compatibility with autoconf < 2.64

> I tried to build the latest urcu (git master e51500) on a Centos 6.2 box, and got:
>
> jscott@dxi0-62:~/src/userspace-rcu$ make -j4
> CDPATH="${ZSH_VERSION+.}:" && cd . && /bin/sh /users/jscott/src/userspace-rcu/config/missing --run aclocal-1.11 -I
> +config
> CDPATH="${ZSH_VERSION+.}:" && cd . && /bin/sh /users/jscott/src/userspace-rcu/config/missing --run autoconf
>  cd . && /bin/sh /users/jscott/src/userspace-rcu/config/missing --run automake-1.11 --foreign
> configure:4010: error: possibly undefined macro: m4_ifnblank
>       If this token and others are legitimate, please use m4_pattern_allow.
>       See the Autoconf documentation.
> make: *** [configure] Error 1
> make: *** Waiting for unfinished jobs....
>
> Some digging showed that the macro m4_ifnblank requires autoconf 2.64. Centos 6.2 has autoconf 2.63. :(
>
> I just worked around it by reverting commit a767fd locally, then I can build fine.

Reported-by: John Steele Scott <toojays@toojays.net>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/config/ax_tls.m4 b/config/ax_tls.m4
index 033e3b135b8d6264e0b3151c3528ae7b3a74c6ca..5ab1a413d1414792e6b0098b7c13a42d56d9bdee 100644 (file)
--- a/config/ax_tls.m4
+++ b/config/ax_tls.m4
@@ -44,7 +44,23 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 10
+#serial 11
+
+#   Define m4_ifblank and m4_ifnblank macros from introduced in
+#   autotools 2.64 m4sugar.m4 if using an earlier autotools.
+
+ifdef([m4_ifblank], [], [
+m4_define([m4_ifblank],
+[m4_if(m4_translit([[$1]],  [ ][       ][
+]), [], [$2], [$3])])
+])
+
+
+ifdef([m4_ifnblank], [], [
+m4_define([m4_ifnblank],
+[m4_if(m4_translit([[$1]],  [ ][       ][
+]), [], [$3], [$2])])
+])
 
 AC_DEFUN([AX_TLS], [
   AC_MSG_CHECKING(for thread local storage (TLS) class)

diff --git a/configure.ac b/configure.ac
index db349358868371ace417a21ca7f17bb8e7547539..6935939fca81583d5e57d7f647f91bd798c0ffcb 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -28,7 +28,7 @@ AH_TEMPLATE([CONFIG_RCU_COMPAT_ARCH], [Compatibility mode for i386 which lacks c
 AH_TEMPLATE([CONFIG_RCU_ARM_HAVE_DMB], [Use the dmb instruction if available for use on ARM.])
 AH_TEMPLATE([CONFIG_RCU_TLS], [TLS provided by the compiler.])
 
-AX_TLS([AC_DEFINE_UNQUOTED([CONFIG_RCU_TLS], $ac_cv_tls)], [])
+AX_TLS(AC_DEFINE_UNQUOTED([CONFIG_RCU_TLS], $ac_cv_tls), [:])
 
 # Checks for programs.
 AC_PROG_CC