diff --git a/dlls/dmstyle/dmutils.c b/dlls/dmstyle/dmutils.c
index 4d8f12f37f4..c732b56e03a 100644
--- a/dlls/dmstyle/dmutils.c
+++ b/dlls/dmstyle/dmutils.c
@@ -256,7 +256,7 @@ const char *debugstr_fourcc (DWORD fourcc) {
 }
 
 /* DMUS_VERSION struct to string conversion for debug messages */
-const char *debugstr_dmversion (LPDMUS_VERSION version) {
+static const char *debugstr_dmversion (LPDMUS_VERSION version) {
 	if (!version) return "'null'";
 	return wine_dbg_sprintf ("\'%i,%i,%i,%i\'",
 		HIWORD(version->dwVersionMS),LOWORD(version->dwVersionMS),
@@ -264,7 +264,7 @@ const char *debugstr_dmversion (LPDMUS_VERSION version) {
 }
 
 /* month number into month name (for debugstr_filetime) */
-const char *debugstr_month (DWORD dwMonth) {
+static const char *debugstr_month (DWORD dwMonth) {
 	switch (dwMonth) {
 		case 1: return "January";
 		case 2: return "February";
@@ -283,7 +283,7 @@ const char *debugstr_month (DWORD dwMonth) {
 }
 
 /* FILETIME struct to string conversion for debug messages */
-const char *debugstr_filetime (LPFILETIME time) {
+static const char *debugstr_filetime (LPFILETIME time) {
 	SYSTEMTIME sysTime;
 
 	if (!time) return "'null'";
@@ -646,7 +646,7 @@ const char* debugstr_flags (DWORD flags, const flag_info* names, size_t num_name
 }
 
 /* dump DMUS_OBJ flags */
-const char *debugstr_DMUS_OBJ_FLAGS (DWORD flagmask) {
+static const char *debugstr_DMUS_OBJ_FLAGS (DWORD flagmask) {
     static const flag_info flags[] = {
 	    FE(DMUS_OBJ_OBJECT),
 	    FE(DMUS_OBJ_CLASS),
@@ -665,7 +665,7 @@ const char *debugstr_DMUS_OBJ_FLAGS (DWORD flagmask) {
 }
 
 /* dump DMUS_CONTAINER flags */
-const char *debugstr_DMUS_CONTAINER_FLAGS (DWORD flagmask) {
+static const char *debugstr_DMUS_CONTAINER_FLAGS (DWORD flagmask) {
     static const flag_info flags[] = {
 	    FE(DMUS_CONTAINER_NOLOADS)
 	};
@@ -673,7 +673,7 @@ const char *debugstr_DMUS_CONTAINER_FLAGS (DWORD flagmask) {
 }
 
 /* dump DMUS_CONTAINED_OBJF flags */
-const char *debugstr_DMUS_CONTAINED_OBJF_FLAGS (DWORD flagmask) {
+static const char *debugstr_DMUS_CONTAINED_OBJF_FLAGS (DWORD flagmask) {
     static const flag_info flags[] = {
 	    FE(DMUS_CONTAINED_OBJF_KEEP)
 	};
diff --git a/dlls/dmstyle/dmutils.h b/dlls/dmstyle/dmutils.h
index 4d3292aa77c..c932fbef288 100644
--- a/dlls/dmstyle/dmutils.h
+++ b/dlls/dmstyle/dmutils.h
@@ -68,10 +68,6 @@ extern BOOL IS_VALID_DMFORM (FOURCC chunkID);
 extern const char *resolve_STREAM_SEEK (DWORD flag);
 /* FOURCC to string conversion for debug messages */
 extern const char *debugstr_fourcc (DWORD fourcc);
-/* DMUS_VERSION struct to string conversion for debug messages */
-extern const char *debugstr_dmversion (LPDMUS_VERSION version);
-/* FILETIME struct to string conversion for debug messages */
-extern const char *debugstr_filetime (LPFILETIME time);
 /* returns name of given GUID */
 extern const char *debugstr_dmguid (const GUID *id);
 /* returns name of given error code */
@@ -79,9 +75,6 @@ extern const char *debugstr_dmreturn (DWORD code);
 /* generic flags-dumping function */
 extern const char *debugstr_flags (DWORD flags, const flag_info* names, size_t num_names);
 
-extern const char *debugstr_DMUS_OBJ_FLAGS (DWORD flagmask);
-extern const char *debugstr_DMUS_CONTAINER_FLAGS (DWORD flagmask);
-extern const char *debugstr_DMUS_CONTAINED_OBJF_FLAGS (DWORD flagmask);
 /* dump whole DMUS_OBJECTDESC struct */
 extern const char *debugstr_DMUS_OBJECTDESC (LPDMUS_OBJECTDESC pDesc);
 extern void        debug_DMUS_OBJECTDESC (LPDMUS_OBJECTDESC pDesc);