diff --git a/Source/exehead/api.h b/Source/exehead/api.h
index 5c225441..55c49839 100644
--- a/Source/exehead/api.h
+++ b/Source/exehead/api.h
@@ -60,6 +60,9 @@ typedef struct
 #ifndef NSISCALL
 #  define NSISCALL __stdcall
 #endif
+#if !defined(_WIN32) && !defined(LPTSTR)
+#  define LPTSTR TCHAR*
+#endif
 
 typedef struct {
   exec_flags_t *exec_flags;
diff --git a/Source/exehead/util.c b/Source/exehead/util.c
index ec5d94c5..01b16955 100644
--- a/Source/exehead/util.c
+++ b/Source/exehead/util.c
@@ -855,7 +855,7 @@ TCHAR * NSISCALL GetNSISString(TCHAR *outbuf, int strtab)
   return ps_tmpbuf;
 }
 
-void NSISCALL validate_filename(LPTSTR in) {
+void NSISCALL validate_filename(TCHAR *in) {
   TCHAR *nono = _T("*?|<>/\":");
   TCHAR *out;
   TCHAR *out_save;
diff --git a/Source/exehead/util.h b/Source/exehead/util.h
index f7817b25..7578bfb1 100644
--- a/Source/exehead/util.h
+++ b/Source/exehead/util.h
@@ -98,7 +98,7 @@ TCHAR * NSISCALL findchar(TCHAR *str, TCHAR c);
 TCHAR * NSISCALL trimslashtoend(TCHAR *buf);
 TCHAR * NSISCALL skip_root(TCHAR *path);
 int NSISCALL is_valid_instpath(TCHAR *s);
-void NSISCALL validate_filename(LPTSTR fn);
+void NSISCALL validate_filename(TCHAR *fn);
 
 /**
  * MoveFileOnReboot tries to move a file by the name of pszExisting to the