net: sockets: Define POSIX function symbols as inline functions
net: sockets: Define POSIX function symbols as inline functions

Previously, POSIX function names were aliased to zsock_ function
names using, for example:

	#define connect zsock_connect

This caused the C preprocessor to replace any symbol named 'connect',
whether a function or not, in all source code which included socket.h,
with 'zsock_connect'.  This generated unintended code where the symbol
'connect' was used as the name of a structure field (as in mqtt.h).

This new inline definition is applied to all the POSIX function symbols,
with the exception of fcntl, a redefinition of which would conflict
with the definiton in the toolchain's fcntl.h.

Fixes #5817

Signed-off-by: Gil Pitney <477da50908f0a7963c2c490cce0ff096d2cac162@linaro.org>

galak/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,Vudentz/zephyr,nashif/zephyr,explora26/zephyr,punitvara/zephyr,mbolivar/zephyr,explora26/zephyr,nashif/zephyr,galak/zephyr,ldts/zephyr,kraj/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,zephyriot/zephyr,galak/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,zephyriot/zephyr,ldts/zephyr,explora26/zephyr,Vudentz/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,mbolivar/zephyr,mbolivar/zephyr,galak/zephyr,kraj/zephyr,zephyriot/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,finikorg/zephyr,punitvara/zephyr,zephyriot/zephyr,Vudentz/zephyr,explora26/zephyr,galak/zephyr,zephyriot/zephyr,nashif/zephyr,nashif/zephyr,kraj/zephyr,finikorg/zephyr,kraj/zephyr,punitvara/zephyr,explora26/zephyr,mbolivar/zephyr,mbolivar/zephyr,nashif/zephyr