pkg.m4: Abort by default if no pkgconf

Provide a second optional argument to PKG_PROG_PKG_CONFIG with an action to
take if no pkgconf is found, and default to aborting.

Too many configure scripts in the wild don't handle an empty PKG_CONFIG,
resulting in weird error messages through the run, which often confuse
users.

Authors wishing to fallback to other methods can either return to the old
behavior by specifying [:] as an action, or use [PKG_CONFIG=false] and call
pkg-config macros normally, handling the fallback as any other failure.

Users can override PKG_CONFIG in the command line so this should imply no
regression.

Closes: https://github.com/pkgconf/pkgconf/issues/350
Ref: https://gitlab.freedesktop.org/pkg-config/pkg-config/-/issues/69
Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
Ismael Luceno 2021-08-26 20:03:44 +02:00 committed by Ariadne Conill
parent 06120a8769
commit c583d49a37
1 changed files with 11 additions and 2 deletions

13
pkg.m4
View File

@ -46,8 +46,8 @@ m4_if(m4_version_compare(PKG_MACROS_VERSION, [$1]), -1,
[m4_fatal([pkg.m4 version $1 or higher is required but ]PKG_MACROS_VERSION[ found])])
])dnl PKG_PREREQ
dnl PKG_PROG_PKG_CONFIG([MIN-VERSION])
dnl ----------------------------------
dnl PKG_PROG_PKG_CONFIG([MIN-VERSION], [ACTION-IF-NOT-FOUND])
dnl ---------------------------------------------------------
dnl Since: 0.16
dnl
dnl Search for the pkg-config tool and set the PKG_CONFIG variable to
@ -55,6 +55,12 @@ dnl first found in the path. Checks that the version of pkg-config found
dnl is at least MIN-VERSION. If MIN-VERSION is not specified, 0.9.0 is
dnl used since that's the first version where most current features of
dnl pkg-config existed.
dnl
dnl If pkg-config is not found or older than specified, it will result
dnl in an empty PKG_CONFIG variable. To avoid widespread issues with
dnl scripts not checking it, ACTION-IF-NOT-FOUND defaults to aborting.
dnl You can specify [PKG_CONFIG=false] as an action instead, which would
dnl result in pkg-config tests failing, but no bogus error messages.
AC_DEFUN([PKG_PROG_PKG_CONFIG],
[m4_pattern_forbid([^_?PKG_[A-Z_]+$])
m4_pattern_allow([^PKG_CONFIG(_(PATH|LIBDIR|SYSROOT_DIR|ALLOW_SYSTEM_(CFLAGS|LIBS)))?$])
@ -75,6 +81,9 @@ if test -n "$PKG_CONFIG"; then
AC_MSG_RESULT([no])
PKG_CONFIG=""
fi
fi
if test -z "$PKG_CONFIG"; then
m4_default([$2], [AC_MSG_ERROR([pkg-config not found])])
fi[]dnl
])dnl PKG_PROG_PKG_CONFIG