Fix linking against musl print functions

When inlining is disabled vfprintf and vfprintf_unfiltered fail to link
if they are not marked as static.

Test: Build trusty with -fno-inline-functions enabled as a global flag
Change-Id: I295a31701f0bf74f459e1af2476be099c7366c32
diff --git a/include/stdio.h b/include/stdio.h
index ea8d69c..1734592 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -113,11 +113,11 @@
 
 int vprintf(const char *__restrict, __isoc_va_list);
 int vfprintf_worker(FILE *__restrict, const char *__restrict, __isoc_va_list, int);
-inline int vfprintf(FILE *__restrict f, const char *__restrict fmt, va_list ap)
+static inline int vfprintf(FILE *__restrict f, const char *__restrict fmt, va_list ap)
 {
 	return vfprintf_worker(f, fmt, ap, 1);
 }
-inline int vfprintf_unfiltered(FILE *__restrict f, const char *__restrict fmt, va_list ap)
+static inline int vfprintf_unfiltered(FILE *__restrict f, const char *__restrict fmt, va_list ap)
 {
 	return vfprintf_worker(f, fmt, ap, 0);
 }