diff --git a/tools_common.h b/tools_common.h
index 7dfd5ad21..068e7b518 100644
--- a/tools_common.h
+++ b/tools_common.h
@@ -12,6 +12,46 @@
 
 #include <stdio.h>
 
+#include "./vpx_config.h"
+
+#if defined(_MSC_VER)
+/* MSVS doesn't define off_t, and uses _f{seek,tell}i64. */
+typedef __int64 off_t;
+#define fseeko _fseeki64
+#define ftello _ftelli64
+#elif defined(_WIN32)
+/* MinGW defines off_t as long and uses f{seek,tell}o64/off64_t for large
+ * files. */
+#define fseeko fseeko64
+#define ftello ftello64
+#define off_t off64_t
+#endif  /* _WIN32 */
+
+#if CONFIG_OS_SUPPORT
+#if defined(_MSC_VER)
+#include <io.h>  /* NOLINT */
+#define snprintf _snprintf
+#define isatty   _isatty
+#define fileno   _fileno
+#else
+#include <unistd.h>  /* NOLINT */
+#endif  /* _MSC_VER */
+#endif  /* CONFIG_OS_SUPPORT */
+
+/* Use 32-bit file operations in WebM file format when building ARM
+ * executables (.axf) with RVCT. */
+#if !CONFIG_OS_SUPPORT
+typedef long off_t;  /* NOLINT */
+#define fseeko fseek
+#define ftello ftell
+#endif  /* CONFIG_OS_SUPPORT */
+
+#define LITERALU64(hi, lo) ((((uint64_t)hi) << 32) | lo)
+
+#ifndef PATH_MAX
+#define PATH_MAX 512
+#endif
+
 #define VP8_FOURCC (0x30385056)
 #define VP9_FOURCC (0x30395056)
 #define VP8_FOURCC_MASK (0x00385056)
diff --git a/vpxdec.c b/vpxdec.c
index 8e575e16f..110e4ac24 100644
--- a/vpxdec.c
+++ b/vpxdec.c
@@ -33,21 +33,6 @@
 #include "nestegg/include/nestegg/nestegg.h"
 #include "third_party/libyuv/include/libyuv/scale.h"
 
-#if CONFIG_OS_SUPPORT
-#if defined(_MSC_VER)
-#include <io.h>
-#define snprintf _snprintf
-#define isatty   _isatty
-#define fileno   _fileno
-#else
-#include <unistd.h>
-#endif
-#endif
-
-#ifndef PATH_MAX
-#define PATH_MAX 256
-#endif
-
 static const char *exec_name;
 
 static const struct {
diff --git a/vpxenc.c b/vpxenc.c
index df75b853a..b9efa18a5 100644
--- a/vpxenc.c
+++ b/vpxenc.c
@@ -49,31 +49,6 @@
 #include "webmenc.h"
 #include "y4minput.h"
 
-
-/* Need special handling of these functions on Windows */
-#if defined(_MSC_VER)
-/* MSVS doesn't define off_t, and uses _f{seek,tell}i64 */
-typedef __int64 off_t;
-#define fseeko _fseeki64
-#define ftello _ftelli64
-#elif defined(_WIN32)
-/* MinGW defines off_t as long
-   and uses f{seek,tell}o64/off64_t for large files */
-#define fseeko fseeko64
-#define ftello ftello64
-#define off_t off64_t
-#endif
-
-#define LITERALU64(hi,lo) ((((uint64_t)hi)<<32)|lo)
-
-/* We should use 32-bit file operations in WebM file format
- * when building ARM executable file (.axf) with RVCT */
-#if !CONFIG_OS_SUPPORT
-typedef long off_t;
-#define fseeko fseek
-#define ftello ftell
-#endif
-
 /* Swallow warnings about unused results of fread/fwrite */
 static size_t wrap_fread(void *ptr, size_t size, size_t nmemb,
                          FILE *stream) {
diff --git a/webmenc.c b/webmenc.c
index a584e9db9..17bbeec78 100644
--- a/webmenc.c
+++ b/webmenc.c
@@ -15,20 +15,6 @@
 #include "third_party/libmkv/EbmlWriter.h"
 #include "third_party/libmkv/EbmlIDs.h"
 
-#if defined(_MSC_VER)
-/* MSVS uses _f{seek,tell}i64 */
-#define fseeko _fseeki64
-#define ftello _ftelli64
-#elif defined(_WIN32)
-/* MinGW defines off_t as long, and uses f{seek,tell}o64/off64_t for large
- * files */
-#define fseeko fseeko64
-#define ftello ftello64
-#define off_t off64_t
-#endif
-
-#define LITERALU64(hi, lo) ((((uint64_t)hi) << 32) | lo)
-
 void Ebml_Write(struct EbmlGlobal *glob,
                 const void *buffer_in,
                 unsigned long len) {