package/php: ffi needs dynamic library

FFI support in php has been added with commit
e16f05c0f00081d446ebee56d9f3ad3cf41da1ae, it depends on dynamic library
otherwise the build will fail on:

/home/buildroot/autobuild/instance-1/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabi/5.5.0/../../../../arm-buildroot-linux-uclibcgnueabi/bin/ld: ext/ffi/ffi.o: in function `zim_FFI_cdef':
ffi.c:(.text+0xe78): undefined reference to `DL_LOAD'

Fixes:
 - http://autobuild.buildroot.org/results/3380b7b6777d1c5fcb53c855b003466fa3bf2079

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/php/Config.ext

@@ -429,12 +429,13 @@ config BR2_PACKAGE_PHP_EXT_XSL
 
 config BR2_PACKAGE_PHP_EXT_FFI
 	bool "FFI"
+	depends on !BR2_STATIC_LIBS
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_LIBFFI
 	help
 	  Foreign Function Interface support
 
-comment "PHP FFI extension needs a toolchain w/ threads"
-	depends on !BR2_TOOLCHAIN_HAS_THREADS
+comment "PHP FFI extension needs a toolchain w/ threads, dynamic library"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS || BR2_STATIC_LIBS
 
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