build: remove check for __declspec(dllexport)

build_msvc/bitcoin_config.h.in

@@ -49,9 +49,6 @@
    */
 #define HAVE_DECL_SETSID 0
 
-/* Define if the dllexport attribute is supported. */
-#define HAVE_DLLEXPORT_ATTRIBUTE 1
-
 /* Define to the address where bug reports for this package should be sent. */
 #define PACKAGE_BUGREPORT "https://github.com/bitcoin/bitcoin/issues"
 

configure.ac

@@ -943,18 +943,6 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
  [ AC_MSG_RESULT([no])]
 )
 
-AC_MSG_CHECKING([for dllexport attribute])
-AC_COMPILE_IFELSE([AC_LANG_SOURCE([
-  __declspec(dllexport) int foo(void);
-  int main(){}
-  ])],
-  [
-    AC_DEFINE([HAVE_DLLEXPORT_ATTRIBUTE], [1], [Define if the dllexport attribute is supported.])
-    AC_MSG_RESULT([yes])
-  ],
-  [AC_MSG_RESULT([no])]
-)
-
 dnl Check for different ways of gathering OS randomness
 AC_MSG_CHECKING([for Linux getrandom function])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[