On MinGW the result of ntohl needs to be casted to uint32_t and
the result of ntohs to uint16_t. To avoid doing this everywhere
add SCNtohl and SCNtohs macros.
This adds new functions that will be called
through unix-socket and permit to update
and show memcap value.
The memcap value needs to be handled in a
thread safe way, so for this reason it is
declared as atomic var.
Another function is added to gets
the memuse value since it will be shown
through unix-socket.
Set flags by default:
-Wmissing-prototypes
-Wmissing-declarations
-Wstrict-prototypes
-Wwrite-strings
-Wcast-align
-Wbad-function-cast
-Wformat-security
-Wno-format-nonliteral
-Wmissing-format-attribute
-funsigned-char
Fix minor compiler warnings for these new flags on gcc and clang.