php: add patch to fix build on static-only systems

This commit adds a patch to PHP to fix the build on static-only
system, a regression introduced in PHP recently.

Fixes:

  http://autobuild.buildroot.net/results/fbf7ebbb9502424727006f39e169ec1ee870186d/



Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>