diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index 4a332a50055..87024e1bfce 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -638,7 +638,7 @@ static int solaris_sigaction( int sig, const struct sigaction *new, struct sigac
 
 #endif
 
-extern void clear_alignment_flag(void);
+extern void clear_alignment_flag(void) DECLSPEC_HIDDEN;
 __ASM_GLOBAL_FUNC( clear_alignment_flag,
                    "pushfl\n\t"
                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
@@ -914,7 +914,7 @@ static inline void restore_context( const struct xcontext *xcontext, ucontext_t
  *
  * Set the new CPU context.
  */
-extern void set_full_cpu_context(void);
+extern void set_full_cpu_context(void) DECLSPEC_HIDDEN;
 __ASM_GLOBAL_FUNC( set_full_cpu_context,
                    "movl %fs:0x1f8,%ecx\n\t"
                    "movl $0,%fs:0x1f8\n\t"    /* x86_thread_data()->syscall_frame = NULL */
@@ -1622,6 +1622,9 @@ struct apc_stack_layout
     CONTEXT       context;
 };
 
+struct apc_stack_layout * WINAPI setup_user_apc_dispatcher_stack( CONTEXT *context, struct apc_stack_layout *stack,
+                                                                  void *arg1, void *arg2, void *arg3,
+                                                                  void *func, NTSTATUS status ) DECLSPEC_HIDDEN;
 struct apc_stack_layout * WINAPI setup_user_apc_dispatcher_stack( CONTEXT *context, struct apc_stack_layout *stack,
                                                                   void *arg1, void *arg2, void *arg3,
                                                                   void *func, NTSTATUS status )
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 0b7dde1b931..dcb0e588c66 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -1568,7 +1568,7 @@ static void restore_context( const struct xcontext *xcontext, ucontext_t *sigcon
  *
  * Set the new CPU context.
  */
-extern void set_full_cpu_context(void);
+extern void set_full_cpu_context(void) DECLSPEC_HIDDEN;
 __ASM_GLOBAL_FUNC( set_full_cpu_context,
                    "movq %gs:0x30,%rdx\n\t"
                    "movq 0x328(%rdx),%rsp\n\t"      /* amd64_thread_data()->syscall_frame */
@@ -1874,7 +1874,7 @@ NTSTATUS get_thread_wow64_context( HANDLE handle, void *ctx, ULONG size )
 }
 
 
-extern void CDECL raise_func_trampoline( void *dispatcher );
+extern void CDECL raise_func_trampoline( void *dispatcher ) DECLSPEC_HIDDEN;
 
 __ASM_GLOBAL_FUNC( raise_func_trampoline,
                    "jmpq *%r8\n\t")
@@ -1971,6 +1971,9 @@ static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
 /***********************************************************************
  *           call_user_apc_dispatcher
  */
+struct apc_stack_layout * WINAPI setup_user_apc_dispatcher_stack( CONTEXT *context,
+                                                                  struct apc_stack_layout *stack,
+                                                                  NTSTATUS status ) DECLSPEC_HIDDEN;
 struct apc_stack_layout * WINAPI setup_user_apc_dispatcher_stack( CONTEXT *context,
                                                                   struct apc_stack_layout *stack,
                                                                   NTSTATUS status )
@@ -2051,6 +2054,9 @@ void WINAPI call_raise_user_exception_dispatcher( NTSTATUS (WINAPI *dispatcher)(
 /***********************************************************************
  *           call_user_exception_dispatcher
  */
+struct stack_layout * WINAPI setup_user_exception_dispatcher_stack( EXCEPTION_RECORD *rec, CONTEXT *context,
+                                               NTSTATUS (WINAPI *dispatcher)(EXCEPTION_RECORD*,CONTEXT*),
+                                               struct stack_layout *stack ) DECLSPEC_HIDDEN;
 struct stack_layout * WINAPI setup_user_exception_dispatcher_stack( EXCEPTION_RECORD *rec, CONTEXT *context,
                                                NTSTATUS (WINAPI *dispatcher)(EXCEPTION_RECORD*,CONTEXT*),
                                                struct stack_layout *stack )
diff --git a/dlls/ntdll/unix/system.c b/dlls/ntdll/unix/system.c
index 01381630600..429f5fe3fb8 100644
--- a/dlls/ntdll/unix/system.c
+++ b/dlls/ntdll/unix/system.c
@@ -197,7 +197,7 @@ static inline void do_cpuid(unsigned int ax, unsigned int cx, unsigned int *p)
 }
 
 #ifdef __i386__
-extern int have_cpuid(void);
+extern int have_cpuid(void) DECLSPEC_HIDDEN;
 __ASM_GLOBAL_FUNC( have_cpuid,
                    "pushfl\n\t"
                    "pushfl\n\t"