reimplemented the endian stuff, using inline asm for x86. #define g_htonl

reimplemented the endian stuff, using inline asm for x86. #define g_htonl

* glib.h: reimplemented the endian stuff, using inline asm for x86.
#define g_htonl and friends.

* testglib.c: new tests for the endian stuff

* configure.in: care for AIX in gmodule linker flags test (from Joel Becker
<jlbec@raleigh.ibm.com>). Check $host_os for linux instead of existance of
/usr/include/linux

* gutils.c: buh-bye evil warning. Thou hast been #ifdef'd out of thine
existance!

-Yosh