Put iconv constiness into CFLAGS

Avoids AC_DEFINE weirdness on Windows.

Author: NattyNarwhal

ext/iconv/config.m4

@@ -83,6 +83,8 @@ int main(void) {
   AS_VAR_IF([php_cv_iconv_errno], [yes],,
     [AC_MSG_FAILURE([The iconv check failed, 'errno' is missing.])])
 
+  dnl iconv on some platforms (NetBSD pre-10, Solaris) may have a non-standard
+  dnl const input parameter; libiconv may imitate this on those platforms.
   AC_CACHE_CHECK([if iconv input parameter is const (non-standard)], [php_cv_iconv_const],
     [AC_COMPILE_IFELSE([AC_LANG_SOURCE([
 #include <iconv.h>
@@ -91,8 +93,6 @@ size_t iconv(iconv_t cd, const char **src, size_t *srcleft, char **dst, size_t *
     ])],
     [php_cv_iconv_const=const],
     [php_cv_iconv_const=])])
-  AC_DEFINE_UNQUOTED([ICONV_CONST], [$php_cv_iconv_const],
-    [Define to const if iconv's input is const.])
 
   AC_CACHE_CHECK([if iconv supports //IGNORE], [php_cv_iconv_ignore],
     [AC_RUN_IFELSE([AC_LANG_SOURCE([
@@ -131,7 +131,7 @@ int main(void) {
   PHP_NEW_EXTENSION([iconv],
     [iconv.c],
     [$ext_shared],,
-    [-DZEND_ENABLE_STATIC_TSRMLS_CACHE=1])
+    [-DZEND_ENABLE_STATIC_TSRMLS_CACHE=1 -DICONV_CONST=$php_cv_iconv_const])
   PHP_SUBST([ICONV_SHARED_LIBADD])
   PHP_INSTALL_HEADERS([ext/iconv], [php_iconv.h])
 fi

ext/iconv/config.w32

@@ -11,10 +11,9 @@ if (PHP_ICONV != "no") {
 
 		AC_DEFINE("HAVE_ICONV", 1, "Define to 1 if the PHP extension 'iconv' is available.");
 		AC_DEFINE("HAVE_LIBICONV", 1, "Define to 1 if you have the 'libiconv' function.");
-		AC_DEFINE("ICONV_CONST", "", "Define to const if iconv's input is const.", false);
 		AC_DEFINE("ICONV_ALIASED_LIBICONV", 1, "Define to 1 if 'iconv()' is aliased to 'libiconv()'.");
 		AC_DEFINE("PHP_ICONV_IMPL", "\"libiconv\"", "The iconv implementation.");
-		ADD_FLAG("CFLAGS_ICONV", "/D PHP_ICONV_EXPORTS ");
+		ADD_FLAG("CFLAGS_ICONV", "/D PHP_ICONV_EXPORTS /D ICONV_CONST ");
 		if (!PHP_ICONV_SHARED) {
 			ADD_DEF_FILE("ext\\iconv\\php_iconv.def");
 		}