Add configuration options.

Makefile.rule

@@ -15,7 +15,7 @@ VERSION = 0.2.13
 # TARGET = PENRYN
 
 # If you want to support multiple architecture in one binary
-#DYNAMIC_ARCH = 1
+# DYNAMIC_ARCH = 1
 
 # C compiler including binary type(32bit / 64bit). Default is gcc.
 # Don't use Intel Compiler or PGI, it won't generate right codes as I expect.
@@ -159,6 +159,19 @@ COMMON_PROF = -pg
 # Build Debug version
 # DEBUG = 1
 
+# Improve GEMV and GER for small matrices by stack allocation.
+# For details, https://github.com/xianyi/OpenBLAS/pull/482
+#
+# MAX_STACK_ALLOC=2048
+
+# Add a prefix or suffix to all exported symbol names in the shared library.
+# Avoid conflicts with other BLAS libraries, especially when using
+# 64 bit integer interfaces in OpenBLAS.
+# For details, https://github.com/xianyi/OpenBLAS/pull/459
+#
+# SYMBOLPREFIX=
+# SYMBOLSUFFIX=
+
 #
 #  End of user configuration
 #