diff --git a/Source/build.cpp b/Source/build.cpp
index 549e869f..5daaaef3 100644
--- a/Source/build.cpp
+++ b/Source/build.cpp
@@ -3232,7 +3232,7 @@ void CEXEBuild::build_plugin_table(void)
   INFO_MSG("\n");
 }
 
-#define FLAG_OFFSET(flag) (FIELD_OFFSET(exec_flags, flag)/sizeof(int))
+#define FLAG_OFFSET(flag) (FIELD_OFFSET(exec_flags_t, flag)/sizeof(int))
 
 int CEXEBuild::add_plugins_dir_initializer(void)
 {
diff --git a/Source/exehead/api.h b/Source/exehead/api.h
index 1f2c153e..a2c988aa 100644
--- a/Source/exehead/api.h
+++ b/Source/exehead/api.h
@@ -34,7 +34,7 @@ enum NSPIM
 // Prototype for callbacks registered with extra_parameters->RegisterPluginCallback()
 // Return NULL for unknown messages
 // Should always be __cdecl for future expansion possibilities
-typedef UINT_PTR (*NSISPLUGINCALLBACK)(NSPIM);
+typedef UINT_PTR (*NSISPLUGINCALLBACK)(enum NSPIM);
 
 // extra_parameters data structures containing other interesting stuff
 // but the stack, variables and HWND passed on to plug-ins.
@@ -55,10 +55,10 @@ typedef struct
   int errlvl;
   int alter_reg_view;
   int status_update;
-} exec_flags;
+} exec_flags_t;
 
 typedef struct {
-  exec_flags *exec_flags;
+  exec_flags_t *exec_flags;
   int (NSISCALL *ExecuteCodeSegment)(int, HWND);
   void (NSISCALL *validate_filename)(char *);
   BOOL (NSISCALL *RegisterPluginCallback)(HMODULE, NSISPLUGINCALLBACK);
diff --git a/Source/exehead/exec.c b/Source/exehead/exec.c
index 4c066fc0..fd33d6c6 100644
--- a/Source/exehead/exec.c
+++ b/Source/exehead/exec.c
@@ -43,8 +43,8 @@ typedef struct _stack_t {
 static stack_t *g_st;
 #endif
 
-exec_flags g_exec_flags;
-exec_flags g_exec_flags_last_used;
+exec_flags_t g_exec_flags;
+exec_flags_t g_exec_flags_last_used;
 
 extra_parameters plugin_extra_parameters = {
   &g_exec_flags,
diff --git a/Source/exehead/exec.h b/Source/exehead/exec.h
index ad2008ec..4777eeb4 100644
--- a/Source/exehead/exec.h
+++ b/Source/exehead/exec.h
@@ -17,8 +17,10 @@
 #ifndef _EXEC_H_
 #define _EXEC_H_
 
-extern exec_flags g_exec_flags;
-extern exec_flags g_exec_flags_last_used;
+#include "api.h"
+
+extern exec_flags_t g_exec_flags;
+extern exec_flags_t g_exec_flags_last_used;
 
 int NSISCALL ExecuteCodeSegment(int pos, HWND hwndProgress); // returns 0 on success
 int NSISCALL ExecuteCallbackFunction(int num); // returns 0 on success
diff --git a/Source/script.cpp b/Source/script.cpp
index 0e06c8fa..972181f5 100644
--- a/Source/script.cpp
+++ b/Source/script.cpp
@@ -897,7 +897,7 @@ int CEXEBuild::process_jump(LineParser &line, int wt, int *offs)
   return 0;
 }
 
-#define FLAG_OFFSET(flag) (FIELD_OFFSET(exec_flags, flag)/sizeof(int))
+#define FLAG_OFFSET(flag) (FIELD_OFFSET(exec_flags_t, flag)/sizeof(int))
 #define SECTION_FIELD_GET(field) (FIELD_OFFSET(section, field)/sizeof(int))
 #define SECTION_FIELD_SET(field) (-1 - (int)(FIELD_OFFSET(section, field)/sizeof(int)))