configure: always set SPHINX_BUILD
During the Sphinx-migration development, I used
SPHINX_BUILD='' in order to skip building info and manual
pages in gcc folder. However, we've got HAS_SPHINX_BUILD
which is the correct flag for that.
With the patch, one will get a nicer error message when
sphinx-build is missing and one builds (explicitly) a target which
depends on it.
PR other/107620
gcc/ChangeLog:
* configure: Regenerate.
* configure.ac: Always set sphinx-build.
libgomp/ChangeLog:
* configure: Regenerate.
* configure.ac: Always set sphinx-build.
libiberty/ChangeLog:
* configure: Regenerate.
* configure.ac: Always set sphinx-build.
libitm/ChangeLog:
* configure: Regenerate.
* configure.ac: Always set sphinx-build.
libquadmath/ChangeLog:
* configure: Regenerate.
* configure.ac: Always set sphinx-build.