echo: fix regression ("echo" with no arguments didn't print newline.

echo: use fputs if no options are given. Code growth ~15 bytes.

Old:
# time ./busybox find $bigdir -exec echo {} \; >/dev/null
real    0m2.038s
user    0m0.761s
sys     0m0.953s

New:
# time ./busybox find $bigdir -exec echo {} \; >/dev/null
real    0m1.781s
user    0m0.781s
sys     0m0.939s

For comparison: without NOFORK:
# time find $bigdir -exec echo {} \; >/dev/null
real    1m51.129s
user    0m38.442s
sys     1m3.350s

1 files changed, 11 insertions, 8 deletions

diff --git a/coreutils/echo.c b/coreutils/echo.c
index 486245508..2ee5002ba 100644
--- a/coreutils/echo.c
+++ b/coreutils/echo.c
@@ -29,7 +29,10 @@ int bb_echo(char **argv)
 {
         const char *arg;
 #if !ENABLE_FEATURE_FANCY_ECHO
-#define eflag '\\'
+        enum {
+                eflag = '\\',
+                nflag = 1,  /* 1 -- print '\n' */
+        };
         ++argv;
 #else
         const char *p;
@@ -39,7 +42,7 @@ int bb_echo(char **argv)
         while (1) {
                 arg = *++argv;
                 if (!arg)
-                        goto ret;
+                        goto newline_ret;
                 if (*arg != '-')
                         break;
 
@@ -68,10 +71,13 @@ int bb_echo(char **argv)
  just_echo:
 #endif
         while (1) {
-                /* arg is already = *argv and isn't NULL */
+                /* arg is already == *argv and isn't NULL */
                 int c;
 
-                while ((c = *arg++)) {
+                if (!eflag) {
+                        /* optimization for very common case */
+                        fputs(arg, stdout);
+                } else while ((c = *arg++)) {
                         if (c == eflag) {       /* Check for escape seq. */
                                 if (*arg == 'c') {
                                         /* '\c' means cancel newline and
@@ -101,13 +107,10 @@ int bb_echo(char **argv)
                 putchar(' ');
         }
 
-#ifdef CONFIG_FEATURE_FANCY_ECHO
+ newline_ret:
         if (nflag) {
                 putchar('\n');
         }
-#else
-        putchar('\n');
-#endif
  ret:
         return fflush(stdout);
 }