Fixed bug 2335 - Fails to build on Debian GNU/kFreeBSD

Felix Geyer

Starting from version 2.0.1 libsdl fails to build on Debian GNU/kFreeBSD in SDL_cpuinfo.c.

GNU/kFreeBSD defines __FreeBSD_kernel__ but not __FreeBSD__.
The #ifdef __FreeBSD__ check should be extended for __FreeBSD_kernel__, see the attached patch.

Build log:
libtool: compile:  gcc -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -DUSING_GENERATED_CONFIG_H -Iinclude -I/«BUILDDIR»/libsdl2-2.0.1+dfsg1/include -mmmx -m3dnow -msse -msse2 -fvisibility=hidden -D_REENTRANT -I/usr/include/dbus-1.0 -I/usr/lib/x86_64-kfreebsd-gnu/dbus-1.0/include -DHAVE_USBHID_H -DUSBHID_NEW -D_REENTRANT -Wall -c /«BUILDDIR»/libsdl2-2.0.1+dfsg1/src/cpuinfo/SDL_cpuinfo.c  -fPIC -DPIC -o build/.libs/SDL_cpuinfo.o
/«BUILDDIR»/libsdl2-2.0.1+dfsg1/src/cpuinfo/SDL_cpuinfo.c: In function 'SDL_GetSystemRAM':
/«BUILDDIR»/libsdl2-2.0.1+dfsg1/src/cpuinfo/SDL_cpuinfo.c:632:35: error: 'HW_MEMSIZE' undeclared (first use in this function)
             int mib[2] = {CTL_HW, HW_MEMSIZE};
                                   ^
/«BUILDDIR»/libsdl2-2.0.1+dfsg1/src/cpuinfo/SDL_cpuinfo.c:632:35: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [build/SDL_cpuinfo.lo] Error 1