Fixed #19. Provided an error msg when the arch is not supported.

Changelog.txt

@@ -12,6 +12,8 @@ common:
 	  openblas_set_num_threads(int num_threads)" when USE_OPENMP=1
 	* Added extern "C" to support C++. Thank Tasio for the patch(Refs 
 	  issue #21 on github)
+	* Provided an error message when the arch is not supported.(Refs 
+	  issue #19 on github)
 
 x86/x86_64:
 	* 

getarch.c

@@ -604,30 +604,41 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef POWER
 #define POWER
 #endif
+#define OPENBLAS_SUPPORTED
 #endif
 
 #if defined(__i386__) || (__x86_64__)
 #include "cpuid_x86.c"
+#define OPENBLAS_SUPPORTED
 #endif
 
 #ifdef __ia64__
 #include "cpuid_ia64.c"
+#define OPENBLAS_SUPPORTED
 #endif
 
 #ifdef __alpha
 #include "cpuid_alpha.c"
+#define OPENBLAS_SUPPORTED
 #endif
 
 #ifdef POWER
 #include "cpuid_power.c"
+#define OPENBLAS_SUPPORTED
 #endif
 
 #ifdef sparc
 #include "cpuid_sparc.c"
+#define OPENBLAS_SUPPORTED
 #endif
 
 #ifdef __mips__
 #include "cpuid_mips.c"
+#define OPENBLAS_SUPPORTED
+#endif
+
+#ifndef OPENBLAS_SUPPORTED
+#error "This arch/CPU is not supported by OpenBLAS."
 #endif
 
 #else