Fix build error on Windows without precompiled headers

Recent refactoring to use uint relied on indirect includes and precompiled
headers for uint to be defined. Explicitly include BLI_sys_types where this
type is used now.

source/blender/freestyle/intern/python/UnaryFunction1D/BPy_UnaryFunction1DUnsigned.cpp

@@ -12,6 +12,8 @@
 
 #include "UnaryFunction1D_unsigned_int/BPy_QuantitativeInvisibilityF1D.h"
 
+#include "BLI_sys_types.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif