tuklib_integer: New Intel C compiler needs immintrin.h.

Thanks to Melanie Blower (Intel) for the patch.
diff --git a/src/common/tuklib_integer.h b/src/common/tuklib_integer.h
index a7fda67..b1e84d5 100644
--- a/src/common/tuklib_integer.h
+++ b/src/common/tuklib_integer.h
@@ -98,6 +98,17 @@
 #endif
 
 
+////////////////////////////////
+// Compiler-specific features //
+////////////////////////////////
+
+// Newer Intel C compilers require immintrin.h for _bit_scan_reverse()
+// and such functions.
+#if defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 1500)
+#	include <immintrin.h>
+#endif
+
+
 ///////////////////
 // Byte swapping //
 ///////////////////