[libvirt] [PATCH v2 6/7] m4: readline: Use pkg-config where possible
With the 7.0 release, readline has finally started shipping
pkg-config support in the form of a readline.pc file.
Unfortunately, most downstreams have yet to catch up with this
change: among Linux distributions in particular, Fedora Rawhide
seems to be the only one installing it at the moment.
Non-Linux operating systems have been faring much better in
this regard: both FreeBSD (through ports) and macOS (through
homebrew) include pkg-config support in their readline package.
This is great news for us, since those are the platforms where
pkg-config is more useful on account of them installing headers
and libraries outside of the respective default search paths.
Our implementation checks whether readline is registered as a
pkg-config package, and if so obtains CFLAGS and LIBS using the
tool; if not, we just keep using the existing logic.
This commit is best viewed with 'git show -w'.
Signed-off-by: Andrea Bolognani <abologna(a)redhat.com>
---
m4/virt-readline.m4 | 47 +++++++++++++++++++++++++++------------------
1 file changed, 28 insertions(+), 19 deletions(-)
diff --git a/m4/virt-readline.m4 b/m4/virt-readline.m4
index 6f0090056a..1bec5deb22 100644
--- a/m4/virt-readline.m4
+++ b/m4/virt-readline.m4
@@ -23,27 +23,36 @@ AC_DEFUN([LIBVIRT_ARG_READLINE],[
AC_DEFUN([LIBVIRT_CHECK_READLINE],[
- # This function is present in all reasonable (5.0+) readline versions;
- # however, the macOS base system contains a library called libedit which
- # takes over the readline name despite lacking many of its features. We
- # want to make sure we only enable readline support when linking against
- # the actual readline library, and the availability of this specific
- # functions is as good a witness for that fact as any.
- AC_CHECK_DECLS([rl_completion_quote_character],
- [], [],
- [[#include <stdio.h>
- #include <readline/readline.h>]])
-
- if test "$ac_cv_have_decl_rl_completion_quote_character" = "no" ;
then
- if test "$with_readline" = "yes" ; then
- AC_MSG_ERROR([readline is missing rl_completion_quote_character])
- else
- with_readline=no;
+ # We have to check for readline.pc's presence beforehand because for
+ # the longest time the library didn't ship a .pc file at all
+ PKG_CHECK_EXISTS([readline], [use_pkgconfig=1], [use_pkgconfig=0])
+
+ if test $use_pkgconfig = 1; then
+ # readline 7.0 is the first version which includes pkg-config support
+ LIBVIRT_CHECK_PKG([READLINE], [readline], [7.0])
+ else
+ # This function is present in all reasonable (5.0+) readline versions;
+ # however, the macOS base system contains a library called libedit which
+ # takes over the readline name despite lacking many of its features. We
+ # want to make sure we only enable readline support when linking against
+ # the actual readline library, and the availability of this specific
+ # functions is as good a witness for that fact as any.
+ AC_CHECK_DECLS([rl_completion_quote_character],
+ [], [],
+ [[#include <stdio.h>
+ #include <readline/readline.h>]])
+
+ if test "$ac_cv_have_decl_rl_completion_quote_character" = "no" ;
then
+ if test "$with_readline" = "yes" ; then
+ AC_MSG_ERROR([readline is missing rl_completion_quote_character])
+ else
+ with_readline=no;
+ fi
fi
- fi
- # The normal library check...
- LIBVIRT_CHECK_LIB([READLINE], [readline], [readline], [readline/readline.h])
+ # The normal library check...
+ LIBVIRT_CHECK_LIB([READLINE], [readline], [readline], [readline/readline.h])
+ fi
# We need this to avoid compilation issues with modern compilers.
# See 9ea3424a178 for a more detailed explanation
--
2.20.1