BUILDING.md: Restore autotools processing instr.

Partially reverts 54014d9c2a41905b7b766057af6728834da64b59.  When
building from a git sandbox, as opposed to from an official source
tarball, it is still necessary to run autoreconf.

Closes #48

diff --git a/BUILDING.md b/BUILDING.md
index 7d794a9879e1f8a802674f579570e638e1d44bc1..94ee1409d80422ae1eb6eeb7fa86001f2928e33a 100644 (file)
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -71,10 +71,14 @@ Solaris/x86 systems (on Solaris, this generates a 32-bit library.  See below
 for 64-bit build instructions.)
 
     cd {source_directory}
+    autoreconf -fiv
     cd {build_directory}
     sh {source_directory}/configure [additional configure flags]
     make
 
+NOTE: Running autoreconf in the source directory is not necessary if building
+libjpeg-turbo from one of the official release tarballs.
+
 This will generate the following files under .libs/:
 
 **libjpeg.a**