Dogfooding

It could also probably be improved further, we've been detecting python
_after_ looking for python-based tools rst2*. Or we can keep unrelated
checks, I don't think it hurts.

configure.ac

@@ -67,7 +67,10 @@ AC_ARG_WITH([dot],
    fi])
 AM_CONDITIONAL(HAVE_DOT,[test "x$DOT" != "xno"])
 
-# Checks for libraries.
+# Check for python.
+_VARNISH_CHECK_PYTHON
+
+# Check for libraries.
 _VARNISH_SEARCH_LIBS(pthread, pthread_create, [thr pthread c_r])
 _VARNISH_CHECK_LIB(rt, clock_gettime)
 _VARNISH_CHECK_LIB(dl, dlopen)
@@ -346,10 +349,6 @@ fi
 
 AM_MISSING_HAS_RUN
 
-AM_PATH_PYTHON([2.7], [], [
-	AC_MSG_ERROR([Python 2.7 or later is needed to build Varnish.])
-])
-
 AC_CHECK_DECL([SO_ACCEPTFILTER],
     AC_DEFINE(HAVE_ACCEPT_FILTERS,1,[Define to 1 if you have accept filters]),
     ,

varnish.m4

@@ -101,6 +101,16 @@ AC_DEFUN([_VARNISH_CHECK_DEVEL], [
 	[CPPFLAGS=$_orig_cppflags]
 ])
 
+# _VARNISH_CHECK_PYTHON
+# ---------------------
+AC_DEFUN([_VARNISH_CHECK_PYTHON], [
+
+	AM_PATH_PYTHON([2.7], [], [
+		AC_MSG_ERROR([Python >= 2.7 is required.])
+	])
+
+])
+
 # _VARNISH_VMOD_CONFIG
 # --------------------
 AC_DEFUN([_VARNISH_VMOD_CONFIG], [
@@ -114,9 +124,7 @@ AC_DEFUN([_VARNISH_VMOD_CONFIG], [
 	AC_REQUIRE([AC_PROG_CPP])
 	AC_REQUIRE([AC_PROG_CPP_WERROR])
 
-	AM_PATH_PYTHON([2.7], [], [
-		AC_MSG_ERROR([Python 2.7 or later is needed to build VMODs.])
-	])
+	_VARNISH_CHECK_PYTHON
 
 	AS_IF([test -z "$RST2MAN"], [
 		AC_MSG_ERROR([rst2man is needed to build VMOD manuals.])