ntdll: Handle Unix lib exception outside Unix stack.

dlls/ntdll/unix/signal_arm.c

@@ -645,7 +645,7 @@ static BOOL handle_syscall_fault( ucontext_t *context, EXCEPTION_RECORD *rec )
     struct syscall_frame *frame = arm_thread_data()->syscall_frame;
     DWORD i;
 
-    if (!is_inside_syscall( context )) return FALSE;
+    if (!is_inside_syscall( context ) && !ntdll_get_thread_data()->jmp_buf) return FALSE;
 
     TRACE( "code=%x flags=%x addr=%p pc=%08x tid=%04x\n",
            rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,

dlls/ntdll/unix/signal_arm64.c

@@ -794,7 +794,7 @@ static BOOL handle_syscall_fault( ucontext_t *context, EXCEPTION_RECORD *rec )
     struct syscall_frame *frame = arm64_thread_data()->syscall_frame;
     DWORD i;
 
-    if (!is_inside_syscall( context )) return FALSE;
+    if (!is_inside_syscall( context ) && !ntdll_get_thread_data()->jmp_buf) return FALSE;
 
     TRACE( "code=%x flags=%x addr=%p pc=%p tid=%04x\n",
            rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,

dlls/ntdll/unix/signal_i386.c

@@ -1697,7 +1697,7 @@ static BOOL handle_syscall_fault( ucontext_t *sigcontext, void *stack_ptr,
     struct syscall_frame *frame = x86_thread_data()->syscall_frame;
     DWORD i, *stack;
 
-    if (!is_inside_syscall( sigcontext )) return FALSE;
+    if (!is_inside_syscall( sigcontext ) && !ntdll_get_thread_data()->jmp_buf) return FALSE;
 
     TRACE( "code=%x flags=%x addr=%p ip=%08x tid=%04x\n",
            rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,

dlls/ntdll/unix/signal_x86_64.c

@@ -2478,7 +2478,7 @@ static BOOL handle_syscall_fault( ucontext_t *sigcontext, EXCEPTION_RECORD *rec,
     struct syscall_frame *frame = amd64_thread_data()->syscall_frame;
     DWORD i;
 
-    if (!is_inside_syscall( sigcontext )) return FALSE;
+    if (!is_inside_syscall( sigcontext ) && !ntdll_get_thread_data()->jmp_buf) return FALSE;
 
     TRACE_(seh)( "code=%x flags=%x addr=%p ip=%lx tid=%04x\n",
                  rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,