Autoconf redefines the M4 builtin macro 'm4_undefine' in such a way that

it fails if the macro that is being undefined is not already defined. To
make this work under all cases and be sure that at a certain point some
specific macro isn't defined we must use the following style in configure:

m4_ifdef([macro], [m4_undefine([macro])])

diff --git a/ares/configure.ac b/ares/configure.ac
index 2d09dbacc0abb7eada8e31c35e75b6e378f92985..09eb4eae9c20c22ae59d710b27e0b3f662552bb1 100644 (file)
--- a/ares/configure.ac
+++ b/ares/configure.ac
@@ -64,11 +64,15 @@ AC_HELP_STRING([--disable-debug],[Disable debug options]),
 )
 
 dnl skip libtool C++ and Fortran compiler checks
+m4_ifdef([AC_PROG_CXX], [m4_undefine([AC_PROG_CXX])])
 m4_defun([AC_PROG_CXX],[])
+m4_ifdef([AC_PROG_F77], [m4_undefine([AC_PROG_F77])])
 m4_defun([AC_PROG_F77],[])
 
 dnl skip libtool C++ and Fortran linker checks
+m4_ifdef([AC_LIBTOOL_CXX], [m4_undefine([AC_LIBTOOL_CXX])])
 m4_defun([AC_LIBTOOL_CXX],[])
+m4_ifdef([AC_LIBTOOL_F77], [m4_undefine([AC_LIBTOOL_F77])])
 m4_defun([AC_LIBTOOL_F77],[])
 
 dnl libtool setup

diff --git a/configure.ac b/configure.ac
index b8a16f8e97716210b0501b55eb7818cb2a6d7e72..d54dd2fc52e0f2a1ca6a494ae8b8a2bc63c2365b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -116,11 +116,15 @@ dnl support building of Windows DLLs
 AC_LIBTOOL_WIN32_DLL
 
 dnl skip libtool C++ and Fortran compiler checks
+m4_ifdef([AC_PROG_CXX], [m4_undefine([AC_PROG_CXX])])
 m4_defun([AC_PROG_CXX],[])
+m4_ifdef([AC_PROG_F77], [m4_undefine([AC_PROG_F77])])
 m4_defun([AC_PROG_F77],[])
 
 dnl skip libtool C++ and Fortran linker checks
+m4_ifdef([AC_LIBTOOL_CXX], [m4_undefine([AC_LIBTOOL_CXX])])
 m4_defun([AC_LIBTOOL_CXX],[])
+m4_ifdef([AC_LIBTOOL_F77], [m4_undefine([AC_LIBTOOL_F77])])
 m4_defun([AC_LIBTOOL_F77],[])
 
 dnl libtool setup