Fix parameter order

`imagecopymerge()` and `imagecopymergegray()` expect the destination
image first, not the other way round.

Author: cmb69

ext/gd/gd.c

@@ -666,8 +666,8 @@ ZEND_BEGIN_ARG_INFO(arginfo_imagecopy, 0)
 ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_INFO(arginfo_imagecopymerge, 0)
-	ZEND_ARG_INFO(0, src_im)
 	ZEND_ARG_INFO(0, dst_im)
+	ZEND_ARG_INFO(0, src_im)
 	ZEND_ARG_INFO(0, dst_x)
 	ZEND_ARG_INFO(0, dst_y)
 	ZEND_ARG_INFO(0, src_x)
@@ -678,8 +678,8 @@ ZEND_BEGIN_ARG_INFO(arginfo_imagecopymerge, 0)
 ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_INFO(arginfo_imagecopymergegray, 0)
-	ZEND_ARG_INFO(0, src_im)
 	ZEND_ARG_INFO(0, dst_im)
+	ZEND_ARG_INFO(0, src_im)
 	ZEND_ARG_INFO(0, dst_x)
 	ZEND_ARG_INFO(0, dst_y)
 	ZEND_ARG_INFO(0, src_x)
@@ -3811,7 +3811,7 @@ PHP_FUNCTION(imagecopy)
 }
 /* }}} */
 
-/* {{{ proto bool imagecopymerge(resource src_im, resource dst_im, int dst_x, int dst_y, int src_x, int src_y, int src_w, int src_h, int pct)
+/* {{{ proto bool imagecopymerge(resource dst_im, resource src_im, int dst_x, int dst_y, int src_x, int src_y, int src_w, int src_h, int pct)
    Merge one part of an image with another */
 PHP_FUNCTION(imagecopymerge)
 {
@@ -3845,7 +3845,7 @@ PHP_FUNCTION(imagecopymerge)
 }
 /* }}} */
 
-/* {{{ proto bool imagecopymergegray(resource src_im, resource dst_im, int dst_x, int dst_y, int src_x, int src_y, int src_w, int src_h, int pct)
+/* {{{ proto bool imagecopymergegray(resource dst_im, resource src_im, int dst_x, int dst_y, int src_x, int src_y, int src_w, int src_h, int pct)
    Merge one part of an image with another */
 PHP_FUNCTION(imagecopymergegray)
 {