Fixed #define style.

We had a mix of styles for declaring function-like macros:

Style A:
#define \
foo() \
do { \
...

Fixed #define style.

We had a mix of styles for declaring function-like macros:

Style A:
#define \
foo() \
do { \
... \
} while (0)

Style B:
#define foo() \
do { \
... \
} while (0)

We had a similar number of occurences of each style:

$ grep -rnI '^\w*(.*\\' | wc -l
244
$ grep -rn 'define.*(.*)' | wc -l
239

(Those regexes aren't perfect, but a very decent approximation.)

Real examples:

$ find src -type f | xargs sed -n '/^nxt_double_is_zero/,/^$/p'
nxt_double_is_zero(f) \
(fabs(f) <= FLT_EPSILON)

$ find src -type f | xargs sed -n '/define nxt_http_field_set/,/^$/p'
#define nxt_http_field_set(_field, _name, _value) \
do { \
(_field)->name_length = nxt_length(_name); \
(_field)->value_length = nxt_length(_value); \
(_field)->name = (u_char *) _name; \
(_field)->value = (u_char *) _value; \
} while (0)

I'd like to standardize on a single style for them, and IMO,
having the identifier in the same line as #define is a better
option for the following reasons:

- Programmers are used to `#define foo() ...` (readability).
- One less line of code.
- The program for finding them is really simple (see below).

function grep_ngx_func()
{
if (($# != 1)); then
>&2 echo "Usage: ${FUNCNAME[0]} <func>";
return 1;
fi;

find src -type f \
| grep '\.[ch]$' \
| xargs grep -l "$1" \
| sort \
| xargs pcregrep -Mn "(?s)^\$[\w\s*]+?^$1\(.*?^}";

find src -type f \
| grep '\.[ch]$' \
| xargs grep -l "$1" \
| sort \
| xargs pcregrep -Mn "(?s)define $1\(.*?^$" \
| sed -E '1s/^[^:]+:[0-9]+:/&\n\n/';
}

$ grep_ngx_func
Usage: grep_ngx_func <func>

$ grep_ngx_func nxt_http_field_set
src/nxt_http.h:98:

#define nxt_http_field_set(_field, _name, _value) \
do { \
(_field)->name_length = nxt_length(_name); \
(_field)->value_length = nxt_length(_value); \
(_field)->name = (u_char *) _name; \
(_field)->value = (u_char *) _value; \
} while (0)

$ grep_ngx_func nxt_sprintf
src/nxt_sprintf.c:56:

u_char * nxt_cdecl
nxt_sprintf(u_char *buf, u_char *end, const char *fmt, ...)
{
u_char *p;
va_list args;

va_start(args, fmt);
p = nxt_vsprintf(buf, end, fmt, args);
va_end(args);

return p;
}

................
Scripted change:
................

$ find src -type f \
| grep '\.[ch]$' \
| xargs sed -i '/define *\\$/{N;s/ *\\\n/ /;s/ //}'

show more ...

Applied nxt_pointer_to() and nxt_value_at() where possible.

Initial version.