Merge pull request #5 from murgatroid99/php_configure_fix

Added libdl include to make the PHP library compile

src/php/ext/grpc/config.m4

@@ -32,6 +32,9 @@ if test "$PHP_GRPC" != "no"; then
   GRPC_SHARED_LIBADD="-lpthread $GRPC_SHARED_LIBADD"
   PHP_ADD_LIBRARY(pthread)
 
+  PHP_ADD_LIBRARY(dl,,GRPC_SHARED_LIBADD)
+  PHP_ADD_LIBRARY(dl)
+
   PHP_ADD_LIBRARY(rt,,GRPC_SHARED_LIBADD)
   PHP_ADD_LIBRARY(rt)