JDK-8187667 fails on GCC 4.4.7 as found on RHEL 6

/mnt/ramdisk/openjdk/hotspot/src/os/linux/vm/os_linux.inline.hpp: In static member function 'static dirent* os::readdir(DIR*, dirent*)':
/mnt/ramdisk/openjdk/hotspot/src/os/linux/vm/os_linux.inline.hpp:140: error: #pragma GCC diagnostic not allowed inside functions
/mnt/ramdisk/openjdk/hotspot/src/os/linux/vm/os_linux.inline.hpp:141: error: #pragma GCC diagnostic not allowed inside functions
/mnt/ramdisk/openjdk/hotspot/src/os/linux/vm/os_linux.inline.hpp:157: error: #pragma GCC diagnostic not allowed inside functions

Moving the pragma to just above the function definition fixes this. We also need to disable pragma warnings on GCC < 4.6, as push/pop weren't available until then.