Make rtapi_vsnprintf.h a system header

Renamed from `vsnprintf.h`.  This was done mainly to fix tests, but
the header could be useful in an out-of-tree comp as well.

src/Makefile

@@ -405,7 +405,8 @@ HEADERS := \
     rtapi/rtapi_stdint.h \
     rtapi/rtapi_ctype.h \
     rtapi/rtapi_errno.h \
-    rtapi/rtapi_string.h
+    rtapi/rtapi_string.h \
+    rtapi/rtapi_vsnprintf.h
 
 # the "headers" target installs all the header files in ../include
 .PHONY: headers

src/rtapi/rtai_rtapi.c

@@ -73,7 +73,7 @@
 
 #include <linux/cpumask.h>	/* NR_CPUS, cpu_online() */
 
-#include "vsnprintf.h"
+#include "rtapi_vsnprintf.h"
 
 #include <rtai.h>
 #include <rtai_sched.h>

src/rtapi/vsnprintf.h → src/rtapi/rtapi_vsnprintf.h

@@ -1,5 +1,5 @@
 /********************************************************************
-* Description: vsnprintf.h
+* Description: rtapi_vsnprintf.h
 *   Implementation of vsnprintf for kernel space.
 *
 *   Derived from the Linux 2.4.18 kernel  (linux/lib/vsprintf.c)

tests/rtapi_printf.0/test.sh

@@ -1,6 +1,6 @@
 #!/bin/bash -xe
 
-g++ -DULAPI -I${HEADERS} -std=c++11 -I../../src/rtapi \
+g++ -DULAPI -I${HEADERS} -std=c++11 -I${HEADERS} \
     -DSIM -rdynamic -L${LIBDIR} \
     -o test_rtapi_vsnprintf test_rtapi_vsnprintf.c
 ./test_rtapi_vsnprintf

tests/rtapi_printf.0/test_rtapi_vsnprintf.c

@@ -16,7 +16,7 @@
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 #include "rtapi.h"
-#include "vsnprintf.h"
+#include "rtapi_vsnprintf.h"
 #include <stdio.h>
 #include <string.h>