*: make "pragma GCC visibility push(hidden)" less ugly

shell/match.h

@@ -1,5 +1,7 @@
 /* match.h - interface to shell ##/%% matching code */
 
+PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
+
 typedef char *(*scan_t)(char *string, char *match, bool zero);
 
 char *scanleft(char *string, char *match, bool zero);
@@ -20,3 +22,5 @@ static inline scan_t pick_scan(char op1, char op2, bool *zero)
 		return op1 == op2 ? scanleft : scanright;
 	}
 }
+
+POP_SAVED_FUNCTION_VISIBILITY

shell/math.h

@@ -72,8 +72,10 @@
  * below for the exact things that are available.
  */
 
-#ifndef _SHELL_MATH_
-#define _SHELL_MATH_
+#ifndef SHELL_MATH_H
+#define SHELL_MATH_H 1
+
+PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 
 #if ENABLE_SH_MATH_SUPPORT_64
 typedef long long arith_t;
@@ -96,4 +98,6 @@ typedef struct arith_eval_hooks {
 
 arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t*);
 
+POP_SAVED_FUNCTION_VISIBILITY
+
 #endif