autoconf-2.72 incompatibility with time_t detection
I got the following warning from configure on main
at 3b8416ac with autoconf-2.72:
./autogen && ./configure
[...]
checking for gcc option to enable large file support... none needed
checking size of time_t... 8
checking size of time_t... 8
./configure: 5614: test: =: unexpected operator
[...]
The relevant snippet is:
if test $ac_cv_sys_file_offset_bits = 64 && \
test $libbsd_sys_time_bits = 32 && \
test $ac_cv_sizeof_time_t = 8
then :
Unfortunately, ac_cv_sys_file_offset_bits
is an autoconf internal which changed!
See https://github.com/ImageMagick/ImageMagick/commit/e119d19f1bae4c75f381544a33759b15e2dca4b5 (quoted):
- For the 'other' case, we were using the value of
ac_cv_sys_file_offset_bits
for-D_FILE_OFFSET_BITS
to pass down into the Perl module build, but autoconf-2.72 drops the use ofac_cv_sys_file_offset_bits
incf09f48841b66fe76f606dd6018bb3a93242a7c9
, so this ends up defining-D_FILE_OFFSET_BITS=
which then breaks the build.