tools: Fix using DBusBasicValue

DBusBasicValue needs a more recent libdbus so use const void * instead
attrib: Fix compilation errors when compiled without optimization

Fix these build errors:

attrib/att.c: In function ‘dec_read_by_grp_req’:
attrib/att.c:165:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
attrib/att.c:170:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
attrib/att.c: In function ‘dec_read_by_type_req’:
attrib/att.c:393:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
attrib/att.c:402:10: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]
build: Fix --disable-optimization configure option

On commit cc9e4e7cae0379864ea06038d92bf7ecc192bba7, this flag was
mistakenly replaced with the behavior of the old --enable-fortify
option.

This patch restores the "-O0" flag when --disable-optimization is used.

Unfortunately, this is not enough to disable build optimization. By
default, autoconf adds -O2 to CFLAGS if the compiler is GCC. AM_CFLAGS
(where -O0 is added with --disable-optimization) is passed as argument
to GCC before autoconf CFLAGS, so it is not possible to override the
default -O2. One solution is to use:

CFLAGS= ./configure --disable-optimization

i.e. remove -O2 from CFLAGS, and let autoconf add -O0.
unit: Add {TEXT,URL}_STR{8,16} tests for sdp_extract_attr()

These tests are for valid data. Other tests might be added later to
check for error paths, but will require separate macros.

{TEXT,URL}_STR32 cannot be tested with the same macros because
sdp_extract_attr() does not support them. They will be tested
separately with other SDP library functions.

As example of failure output, if commit
504a0cf46ad89cab8005ce9cffb22e41048f6a30 is reverted for testing, the
STR16 test will fail with:

ERROR:unit/test-sdp.c:776:test_sdp_de_attr: assertion failed
(test->input_size == size): (7 == 11)
unit: Add tests for SDP integer Data Elements

SDP_DATA_NIL does not have a value, but its sdp_data_t val field is
zeroed by memset(), so just treat it as UINT8 with zero value to
simplify checking (and not require a separate macro.)

SDP_BOOL is handled by SDP library as a INT8.

SDP_UINT128/SDP_INT128 are just byte arrays converted to host order, so
use memcmp() to compare them (converting from host to network order
first.)