Respect mathematical operation order piority with the exponent gnu extension

Obtained from:	OpenBSD
Approved by:	des (mentor)

usr.bin/m4/parser.y

@@ -17,8 +17,8 @@
  *
  * $FreeBSD$
  */
-#include <stdint.h>
 #include <math.h>
+#include <stdint.h>
 #define YYSTYPE	int32_t
 extern int32_t end_result;
 extern int yylex(void);
@@ -35,9 +35,9 @@ extern int yyparse(void);
 %left EQ NE
 %left '<' LE '>' GE
 %left LSHIFT RSHIFT
-%right EXPONENT
 %left '+' '-'
 %left '*' '/' '%'
+%right EXPONENT
 %right UMINUS UPLUS '!' '~'
 
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