diff --git a/main/php_variables.c b/main/php_variables.c
index 6f6bd6e2066..73e19a856a0 100644
--- a/main/php_variables.c
+++ b/main/php_variables.c
@@ -28,6 +28,9 @@
 
 #include "zend_globals.h"
 
+/* for systems that need to override reading of environment variables */
+void _php_import_environment_variables(zval *array_ptr TSRMLS_DC);
+PHPAPI void (*php_import_environment_variables)(zval *array_ptr TSRMLS_DC) = _php_import_environment_variables;
 
 PHPAPI void php_register_variable(char *var, char *strval, zval *track_vars_array TSRMLS_DC)
 {
@@ -318,8 +321,7 @@ SAPI_API SAPI_TREAT_DATA_FUNC(php_default_treat_data)
 	}
 }
 
-
-void php_import_environment_variables(zval *array_ptr TSRMLS_DC)
+void _php_import_environment_variables(zval *array_ptr TSRMLS_DC)
 {
 	char **env, *p, *t;
 
diff --git a/main/php_variables.h b/main/php_variables.h
index 8321c57d1cd..38d3d3ec440 100644
--- a/main/php_variables.h
+++ b/main/php_variables.h
@@ -31,7 +31,7 @@
 #define PARSE_STRING 3
 
 void php_treat_data(int arg, char *str, zval* destArray TSRMLS_DC);
-PHPAPI void php_import_environment_variables(zval *array_ptr TSRMLS_DC);
+extern PHPAPI void (*php_import_environment_variables)(zval *array_ptr TSRMLS_DC);
 PHPAPI void php_register_variable(char *var, char *val, pval *track_vars_array TSRMLS_DC);
 /* binary-safe version */
 PHPAPI void php_register_variable_safe(char *var, char *val, int val_len, pval *track_vars_array TSRMLS_DC);