Remove "EXAMPLE" from LWIP header (#2128)

The lwipopts.h file started with the PicoW example one, but no longer
tracks it, so remove the EXAMPLE define guard.

Author: earlephilhower

include/lwipopts.h

@@ -1,11 +1,9 @@
-#ifndef _LWIPOPTS_EXAMPLE_COMMONH_H
-#define _LWIPOPTS_EXAMPLE_COMMONH_H
+#pragma once
 
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
 
-
 // Critical section protection
 extern void noInterrupts();
 extern void interrupts();
@@ -108,6 +106,3 @@ extern void __setSystemTime(unsigned long long sec, unsigned long us);
 #ifdef __cplusplus
 }
 #endif // __cplusplus
-
-
-#endif /* __LWIPOPTS_H__ */

lib/libpico.a

@@ -1,11 +1,9 @@
-#ifndef _LWIPOPTS_EXAMPLE_COMMONH_H
-#define _LWIPOPTS_EXAMPLE_COMMONH_H
+#pragma once
 
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
 
-
 // Critical section protection
 extern void noInterrupts();
 extern void interrupts();
@@ -108,6 +106,3 @@ extern void __setSystemTime(unsigned long long sec, unsigned long us);
 #ifdef __cplusplus
 }
 #endif // __cplusplus
-
-
-#endif /* __LWIPOPTS_H__ */