sw:vec-iree: Add LOG_x support for QEMU Linux userspace emulation

Use fprintf as the stub for springbok LOG_x. QEMU Linux userspace emulation
would have the same print out as springbok simulation

```
$ out/host/qemu/qemu-riscv32 -cpu rv32,x-v=true,vlen=512,elen=32,vext_spec=v1.0 out/springbok_iree/samples/quant_model_embedding/daredevil_embedded_sync

Output #0 data length: 527

[[ iree_hal_allocator_t memory statistics ]]
  HOST_LOCAL:            0B peak /            0B allocated /            0B freed /            0B live
DEVICE_LOCAL:      1445663B peak /      1445663B allocated /      1445663B freed /            0B live
daredevil_quant finished successfully
```

Change-Id: Iced7b463537a491133add33f838c4c29a78ddfca

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e82e6aa..3caaac7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,9 +52,10 @@
 # Springbok BSP-related setting
 if(${BUILD_WITH_SPRINGBOK})
   include(riscv_springbok)
-else()
-  # Add the LOG_X header file for build compatibility.
   include_directories($ENV{ROOTDIR}/sw/vec/springbok/include)
+else()
+  # Add the LOG_X springbok macros with fprintf.
+  include_directories(native_log_include)
 endif()
 
 # Build IREE runtime libraries.

native_log_include/springbok.h

diff --git a/native_log_include/springbok.h b/native_log_include/springbok.h
new file mode 100644
index 0000000..d56c2f4
--- /dev/null
+++ b/native_log_include/springbok.h
@@ -0,0 +1,13 @@
+// Stub out the LOG implmentations with fprintf
+#ifndef SPRINGBOK_H
+#define SPRINGBOK_H
+
+#include <stdio.h>
+
+#define LOG_NOISY(msg,args...) fprintf(stdout, msg"\n", ##args)
+#define LOG_DEBUG(msg,args...) fprintf(stdout, msg"\n", ##args)
+#define LOG_INFO(msg,args...) fprintf(stdout, msg"\n", ##args)
+#define LOG_WARN(msg,args...) fprintf(stdout, msg"\n", ##args)
+#define LOG_ERROR(msg, args...) fprintf(stderr, msg"\n", ##args)
+
+#endif  // SPRINGBOK_H

samples/util/CMakeLists.txt

diff --git a/samples/util/CMakeLists.txt b/samples/util/CMakeLists.txt
index b004f46..b700268 100644
--- a/samples/util/CMakeLists.txt
+++ b/samples/util/CMakeLists.txt
@@ -1,5 +1,3 @@
-include_directories($ENV{ROOTDIR}/sw/vec/springbok/include)
-
 iree_cc_library(
   NAME
     util