Make shgemm kernels conditional on BUILD_HALF

kernel/CMakeLists.txt

@@ -137,7 +137,10 @@ function (build_core TARGET_CORE KDIR TSUFFIX KERNEL_DEFINITIONS)
     foreach (float_type SINGLE DOUBLE HALF)
       string(SUBSTRING ${float_type} 0 1 float_char)
       if (${float_type} STREQUAL "HALF")
-	set (float_char "SH")
+        if (NOT ${BUILD_HALF})
+	  continue ()
+        else
+	  set (float_char "SH")
       endif ()
       GenerateNamedObjects("${KERNELDIR}/${${float_char}GEMMKERNEL}" "" "gemm_kernel" false "" "" false ${float_type})
     endforeach()