fix C compiler warnings about unused parameters in buffer format utility functions

Cython/Utility/Buffer.c

@@ -362,7 +362,7 @@ typedef struct { char c; void *x; } __Pyx_st_void_p;
 typedef struct { char c; PY_LONG_LONG x; } __Pyx_st_longlong;
 #endif
 
-static size_t __Pyx_BufFmt_TypeCharToAlignment(char ch, int is_complex) {
+static size_t __Pyx_BufFmt_TypeCharToAlignment(char ch, CYTHON_UNUSED int is_complex) {
   switch (ch) {
     case '?': case 'c': case 'b': case 'B': case 's': case 'p': return 1;
     case 'h': case 'H': return sizeof(__Pyx_st_short) - sizeof(short);
@@ -396,7 +396,7 @@ typedef struct { void *x; char c; } __Pyx_pad_void_p;
 typedef struct { PY_LONG_LONG x; char c; } __Pyx_pad_longlong;
 #endif
 
-static size_t __Pyx_BufFmt_TypeCharToPadding(char ch, int is_complex) {
+static size_t __Pyx_BufFmt_TypeCharToPadding(char ch, CYTHON_UNUSED int is_complex) {
   switch (ch) {
     case '?': case 'c': case 'b': case 'B': case 's': case 'p': return 1;
     case 'h': case 'H': return sizeof(__Pyx_pad_short) - sizeof(short);