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/        //}'

1 files changed, 28 insertions, 56 deletions

diff --git a/src/nxt_buf.h b/src/nxt_buf.h
index 5121d659..f1e2879f 100644
--- a/src/nxt_buf.h
+++ b/src/nxt_buf.h
@@ -113,127 +113,100 @@ struct nxt_buf_s {
 #define NXT_BUF_SYNC_LAST   4
 
 
-#define                                                                       \
-nxt_buf_is_mem(b)                                                             \
+#define nxt_buf_is_mem(b)                                                     \
     ((b)->mem.pos != NULL)
 
 
-#define                                                                       \
-nxt_buf_is_file(b)                                                            \
+#define nxt_buf_is_file(b)                                                    \
     ((b)->is_file)
 
-#define                                                                       \
-nxt_buf_set_file(b)                                                           \
+#define nxt_buf_set_file(b)                                                   \
     (b)->is_file = 1
 
-#define                                                                       \
-nxt_buf_clear_file(b)                                                         \
+#define nxt_buf_clear_file(b)                                                 \
     (b)->is_file = 0
 
 
-#define                                                                       \
-nxt_buf_is_mmap(b)                                                            \
+#define nxt_buf_is_mmap(b)                                                    \
     ((b)->is_mmap)
 
-#define                                                                       \
-nxt_buf_set_mmap(b)                                                           \
+#define nxt_buf_set_mmap(b)                                                   \
     (b)->is_mmap = 1
 
-#define                                                                       \
-nxt_buf_clear_mmap(b)                                                         \
+#define nxt_buf_clear_mmap(b)                                                 \
     (b)->is_mmap = 0
 
 
-#define                                                                       \
-nxt_buf_is_port_mmap(b)                                                       \
+#define nxt_buf_is_port_mmap(b)                                               \
     ((b)->is_port_mmap)
 
-#define                                                                       \
-nxt_buf_set_port_mmap(b)                                                      \
+#define nxt_buf_set_port_mmap(b)                                              \
     (b)->is_port_mmap = 1
 
-#define                                                                       \
-nxt_buf_clear_port_mmap(b)                                                    \
+#define nxt_buf_clear_port_mmap(b)                                            \
     (b)->is_port_mmap = 0
 
 
-#define                                                                       \
-nxt_buf_is_sync(b)                                                            \
+#define nxt_buf_is_sync(b)                                                    \
     ((b)->is_sync)
 
-#define                                                                       \
-nxt_buf_set_sync(b)                                                           \
+#define nxt_buf_set_sync(b)                                                   \
     (b)->is_sync = 1
 
-#define                                                                       \
-nxt_buf_clear_sync(b)                                                         \
+#define nxt_buf_clear_sync(b)                                                 \
     (b)->is_sync = 0
 
 
-#define                                                                       \
-nxt_buf_is_nobuf(b)                                                           \
+#define nxt_buf_is_nobuf(b)                                                   \
     ((b)->is_nobuf)
 
-#define                                                                       \
-nxt_buf_set_nobuf(b)                                                          \
+#define nxt_buf_set_nobuf(b)                                                  \
     (b)->is_nobuf = 1
 
-#define                                                                       \
-nxt_buf_clear_nobuf(b)                                                        \
+#define nxt_buf_clear_nobuf(b)                                                \
     (b)->is_nobuf = 0
 
 
-#define                                                                       \
-nxt_buf_is_flush(b)                                                           \
+#define nxt_buf_is_flush(b)                                                   \
     ((b)->is_flush)
 
-#define                                                                       \
-nxt_buf_set_flush(b)                                                          \
+#define nxt_buf_set_flush(b)                                                  \
     (b)->is_flush = 1
 
-#define                                                                       \
-nxt_buf_clear_flush(b)                                                        \
+#define nxt_buf_clear_flush(b)                                                \
     (b)->is_flush = 0
 
 
-#define                                                                       \
-nxt_buf_is_last(b)                                                            \
+#define nxt_buf_is_last(b)                                                    \
     ((b)->is_last)
 
-#define                                                                       \
-nxt_buf_set_last(b)                                                           \
+#define nxt_buf_set_last(b)                                                   \
     (b)->is_last = 1
 
-#define                                                                       \
-nxt_buf_clear_last(b)                                                         \
+#define nxt_buf_clear_last(b)                                                 \
     (b)->is_last = 0
 
 
-#define                                                                       \
-nxt_buf_mem_set_size(bm, size)                                                \
+#define nxt_buf_mem_set_size(bm, size)                                        \
     do {                                                                      \
         (bm)->start = 0;                                                      \
         (bm)->end = (void *) size;                                            \
     } while (0)
 
 
-#define                                                                       \
-nxt_buf_mem_size(bm)                                                          \
+#define nxt_buf_mem_size(bm)                                                  \
     ((bm)->end - (bm)->start)
 
 
-#define                                                                       \
-nxt_buf_mem_used_size(bm)                                                     \
+#define nxt_buf_mem_used_size(bm)                                             \
     ((bm)->free - (bm)->pos)
 
 
-#define                                                                       \
-nxt_buf_mem_free_size(bm)                                                     \
+#define nxt_buf_mem_free_size(bm)                                             \
     ((bm)->end - (bm)->free)
 
 
-#define                                                                       \
-nxt_buf_used_size(b)                                                          \
+#define nxt_buf_used_size(b)                                                  \
     (nxt_buf_is_file(b) ? (b)->file_end - (b)->file_pos:                      \
                           nxt_buf_mem_used_size(&(b)->mem))
 
@@ -264,8 +237,7 @@ nxt_buf_chk_make_plain(nxt_mp_t *mp, nxt_buf_t *src, size_t size)
     return src;
 }
 
-#define                                                                       \
-nxt_buf_free(mp, b)                                                           \
+#define nxt_buf_free(mp, b)                                                   \
     nxt_mp_free((mp), (b))