build: Don't overwrite CC variable

Don't reset the variable CC in the Makefile, but set it to gcc by
default (can be overriden when e.g. compiling with `make CC=clang').
This way we can also have non-verbose compiles with compilers other than
gcc. Furthermore make sure that the CC variable is also respected for
LD.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
netsniff-ng: Remove useless check for ctx.device_in

If ctx.device_in is NULL after option parsing, it is always set to
"any", which is before this check. Thus, it serves no purpose and can be
removed.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
sock: Error out if setting of the system socket memory fails

Currently we ignore the return value of the write() calls to
/proc/sys/net/core/{r,w}mem_{default,max} in set_system_socket_mem().
Better check the return value and notify the user about it.

This also fixes a clang compiler warning about a variable explicitely
assigned to itself.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
dissector: Don't re-initialize packet_types array

Both sparse and clang warn about the initializers overriding previous
initialization of the packet_types array. Since every access of the
packet_types array checks the value for NULL (the default value, since the
array is static) and prints a "?" if it isNULL, we don't need the prior
initialization with "?".

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
dissectors: 80211_mac_hdr:

clang gives the following warning about function meas_type():

proto_80211_mac_hdr.c:1704:1: warning: control may reach end of non-void function [-Wreturn-type]
}
^

Even though this is a false positive (since we check the entire range of
an u8 in the switch/case), fix it by turning the case 13 ... 255 into
default.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
dissectors: 80211_mac_hdr: Remove remaining binary constants

Commit 151fd88f7429 ("dissectors: 80211_mac_hdr: Remove usage of binary
constants") removed binary constants in a particular case that was
reported to cause a compile error. However, this module uses binary
constants in some other places. Replace them by hexadecimal constants,
which makes it easier to read and is C99 compatible.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>