README: add the autoconf version needed to compile the project

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

diff --git a/README.md b/README.md
index 669a4d36677ae29d5c37d342a640e95325b485a3..dee8fe7c3a1e64b90dfd61fab9fad179eca0d9c2 100644 (file)
--- a/README.md
+++ b/README.md
@@ -30,6 +30,8 @@ BUILDING
 This is a pretty standard autotools project. It does not depend on any
 libraries other than the standard C library with GNU extensions.
 
+The autoconf version needed to compile the project is 2.61.
+
 Recent (as in >= v4.7) kernel headers are also required for the GPIO user
 API definitions.