This replaces the AC_MSG_ERROR with AC_MSG_FAILURE, where appropriate.
The AC_MSG_ERROR outputs given message and exits the configure step. The
AC_MSG_FAILURE does the same but also automatically outputs additional
message "See 'config.log' for more details." which might help directing
the user where to look further.
The AC_MSG_ERROR is used for errors where current test step isn't logged
in the config.log and wouldn't make sense, and AC_MSG_FAILURE is mostly
used in cases of library checks, compilation tests, headers checked with
AC_CHECK_HEADER* and similar tests that are also logged in the
config.log.
AC_MSG_ERROR([Sanity check failed.]) output:
```
configure: error: Sanity check failed.
```
AC_MSG_FAILURE([Sanity check failed.]) output:
```
configure: error: in '/path/to/php-src':
configure: error: Sanity check failed.
See 'config.log' for more details
```
The m4_normalize is for Autoconf < 2.70 (on 2.70 and later versions a
blank-or-newline separated items can be expanded without using
backslash-newline). The order of headers in configure.ac is left as is
because the first few headers depend on checking other headers (for
those includes the 4th argument).
Normalization include:
- Use dnl for everything that can be ommitted when configure is built in
favor of the shell comment character # which is visible in the output.
- Line length normalized to 80 columns
- Dots for most of the one line sentences
- Macro definitions include similar pattern header comments now
The $Id$ keywords were used in Subversion where they can be substituted
with filename, last revision number change, last changed date, and last
user who changed it.
In Git this functionality is different and can be done with Git attribute
ident. These need to be defined manually for each file in the
.gitattributes file and are afterwards replaced with 40-character
hexadecimal blob object name which is based only on the particular file
contents.
This patch simplifies handling of $Id$ keywords by removing them since
they are not used anymore.
