php: fix build for xtensa

The php package generates a binary that is too large for the xtensa default
placement of literals in a dedicated section. Use -mtext-section-literal to
place literals in the text section.

Fixes
http://autobuild.buildroot.net/results/a9a/a9a1063104402ec28e01560ec7c8f8a5b6d43dd5/.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/php/php.mk

@@ -36,6 +36,10 @@ ifneq ($(BR2_INET_IPV6),y)
 endif
 endif
 
+ifeq ($(BR2_xtensa),y)
+PHP_CFLAGS += -mtext-section-literals
+endif
+
 PHP_CONF_OPT += $(if $(BR2_PACKAGE_PHP_CLI),,--disable-cli)
 PHP_CONF_OPT += $(if $(BR2_PACKAGE_PHP_CGI),,--disable-cgi)