improve support for DragonFlyBSD

[Bruno Haible]

With DragonFlyBSD 3.8 / i386 I see these problems in a gnulib testdir:

1) A warning

freadahead.c: In function 'freadahead':
freadahead.c:39:3: warning: implicit declaration of function '__sreadahead' 
[-Wimplicit-function-declaration]

2) A failure
FAIL: test-get-rusage-data
(assertion failed at test-get-rusage-data:60)

3) A failure
FAIL: test-localeconv
(assertion failed at test-localeconv.c:41)

4)
FAIL: test-select
Invalid fd test... failed

Fixed through the attached changesets.


NOT FIXED:

1)
FAIL: test-dup2
(assertion failed at test-dup2.c:163)

FAIL: test-getdtablesize
(assertion failed in test-getdtablesize.c:32)

2) A warning

test-float.c: In function 'test_long_double':
test-float.c:315:5: warning: floating constant exceeds range of 'long double' 
[-Woverflow]

and failures

FAIL: test-float
(assertion failed at test-float.c:318)

FAIL: test-fmal2
(assertion failed at test-fma2.h:538)

3) A failure
FAIL: test-localename
(assertion failed at test-localename.c:183)
LC_CTYPE inheritance appears to be broken.

0001-freadahead-Silence-warning-on-DragonFlyBSD.patch
Description: Text Data

0002-Fix-test-failures-on-DragonFlyBSD.patch
Description: Text Data