fix problem with yy_size_t vs int param to lexer_input

BSD yacc uses "int" for this param, linux uses size_t

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/exp/expression-parser.y b/exp/expression-parser.y
index e4373d4..83b5b30 100644
--- a/exp/expression-parser.y
+++ b/exp/expression-parser.y
@@ -21,6 +21,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <math.h>
+#include "lexer.h"
+
 struct parser_value_type {
 	double dval;
 	long long ival;
@@ -186,7 +188,7 @@
 static int lexer_read_offset = 0;
 static char lexer_input_buffer[1000];
 
-int lexer_input(char* buffer, int *bytes_read, int bytes_requested)
+int lexer_input(char* buffer, yy_size_t *bytes_read, int bytes_requested)
 {
 	int bytes_left = strlen(lexer_input_buffer) - lexer_read_offset;