Merge branch 'maint-0.4.5' into maint-0.4.6

changes/autoconf-2.70

+  o Minor features (compilation):
+    - Make the autoconf script build correctly with autoconf versions 2.70
+      and later. Closes part of ticket 40335.

configure.ac

@@ -454,7 +454,11 @@ AM_CONDITIONAL(BUILD_MANPAGE, [test "x$enable_manpage" != "xno"])
 AM_CONDITIONAL(BUILD_HTML_DOCS, [test "x$enable_html_manual" != "xno"])
 
 AM_PROG_CC_C_O
-AC_PROG_CC_C99
+
+dnl Before autoconf 2.70, AC_PROG_CC_C99 is supposedly necessary for some
+dnl compilers if you wan't C99 support. Starting with 2.70, it is obsolete and
+dnl forbidden.
+m4_version_prereq([2.70], [:], [AC_PROG_CC_C99])
 
 AC_CACHE_CHECK([for Python 3], [tor_cv_PYTHON],
    [AC_PATH_PROGS_FEATURE_CHECK([PYTHON], [ \