Add option USE_LOCKING but keep default settings intact

Makefile.rule

@@ -56,7 +56,7 @@ VERSION = 0.3.7.dev
 # specify it.
 # For force setting for single threaded, specify USE_THREAD = 0
 # For force setting for multi  threaded, specify USE_THREAD = 1
-USE_THREAD = 0
+# USE_THREAD = 0
 
 # If you want to build a single-threaded OpenBLAS, but expect to call this
 # from several concurrent threads in some other program, comment this in for
@@ -226,7 +226,7 @@ NO_AFFINITY = 1
 COMMON_PROF = -pg
 
 # Build Debug version
-DEBUG = 1
+# DEBUG = 1
 
 # Set maximum stack allocation.
 # The default value is 2048. 0 disable stack allocation a may reduce GER and GEMV