[v5,1/2] build: select deprecated libraries

  Rework deprecated libraries selection by introducing a new configuration
option.

This breaks existing configurations that were relying on disable_libs=''
for enabling deprecated libraries.
On the other hand, it will make enabling optional libraries more
straightforward by taking the deprecated libraries out of the picture.

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
Changes since v4:
- changed the option to a list of libraries instead of a global on/off
  knob,
- moved all deprecated libs checks under a single block for readability,

---
 .ci/linux-build.sh            |  2 +-
 devtools/test-meson-builds.sh |  8 ++++----
 lib/meson.build               | 28 ++++++++++++++++++++--------
 meson_options.txt             |  4 +++-
 4 files changed, 28 insertions(+), 14 deletions(-)
  

David Marchand <david.marchand@redhat.com> writes:

> Rework deprecated libraries selection by introducing a new configuration
> option.
>
> This breaks existing configurations that were relying on disable_libs=''
> for enabling deprecated libraries.
> On the other hand, it will make enabling optional libraries more
> straightforward by taking the deprecated libraries out of the picture.
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
> Changes since v4:
> - changed the option to a list of libraries instead of a global on/off
>   knob,
> - moved all deprecated libs checks under a single block for readability,

Looks nice.  I guess we can also update
guides/prog_guide/kernel_nic_interface.rst
guides/prog_guide/flow_classify_lib.rst

with something like the following:

diff --git a/doc/guides/prog_guide/flow_classify_lib.rst b/doc/guides/prog_guide/flow_classify_lib.rst
index ad2e10ec26..c2706b8d46 100644
--- a/doc/guides/prog_guide/flow_classify_lib.rst
+++ b/doc/guides/prog_guide/flow_classify_lib.rst
@@ -10,8 +10,9 @@ Flow Classification Library
    See :doc:`../rel_notes/deprecation`.
 
    It is disabled by default in the DPDK build.
-   To re-enable the library, remove 'flow_classify' from the "disable_libs"
-   meson option when configuring a build.
+   To re-enable the library, tell meson to enable 'flow_classify' as part of
+   the deprecated libraries meson
+   option ``-Denable_deprecated_libs=flow_classify``.
 
 DPDK provides a Flow Classification library that provides the ability
 to classify an input packet by matching it against a set of Flow rules.
diff --git a/doc/guides/prog_guide/kernel_nic_interface.rst b/doc/guides/prog_guide/kernel_nic_interface.rst
index 392e5df75f..1097ecc695 100644
--- a/doc/guides/prog_guide/kernel_nic_interface.rst
+++ b/doc/guides/prog_guide/kernel_nic_interface.rst
@@ -18,7 +18,8 @@ Kernel NIC Interface
 .. note::
 
    KNI is disabled by default in the DPDK build.
-   To re-enable the library, remove 'kni' from the "disable_libs" meson option when configuring a build.
+   To re-enable the library, tell meson to enable 'kni' as part of the
+   deprecated libraries meson option ``-Denable_deprecated_libs=kni``.
 
 The DPDK Kernel NIC Interface (KNI) allows userspace applications access to the Linux* control plane.
 
---

> ---
>  .ci/linux-build.sh            |  2 +-
>  devtools/test-meson-builds.sh |  8 ++++----
>  lib/meson.build               | 28 ++++++++++++++++++++--------
>  meson_options.txt             |  4 +++-
>  4 files changed, 28 insertions(+), 14 deletions(-)
>
> diff --git a/.ci/linux-build.sh b/.ci/linux-build.sh
> index 45f2729996..e0b62bac90 100755
> --- a/.ci/linux-build.sh
> +++ b/.ci/linux-build.sh
> @@ -97,7 +97,7 @@ if [ "$MINI" = "true" ]; then
>      OPTS="$OPTS -Denable_drivers=net/null"
>      OPTS="$OPTS -Ddisable_libs=*"
>  else
> -    OPTS="$OPTS -Ddisable_libs="
> +    OPTS="$OPTS -Denable_deprecated_libs=*"
>  fi
>  OPTS="$OPTS -Dlibdir=lib"
>  
> diff --git a/devtools/test-meson-builds.sh b/devtools/test-meson-builds.sh
> index 84b907d2ea..c41659d28b 100755
> --- a/devtools/test-meson-builds.sh
> +++ b/devtools/test-meson-builds.sh
> @@ -120,10 +120,10 @@ config () # <dir> <builddir> <meson options>
>  		return
>  	fi
>  	options=
> -	# deprecated libs may be disabled by default, so for complete builds ensure
> -	# no libs are disabled
> -	if ! echo $* | grep -q -- 'disable_libs' ; then
> -		options="$options -Ddisable_libs="
> +	# deprecated libs are disabled by default, so for complete builds
> +	# enable them
> +	if ! echo $* | grep -q -- 'enable_deprecated_libs' ; then
> +		options="$options -Denable_deprecated_libs=*"
>  	fi
>  	if echo $* | grep -qw -- '--default-library=shared' ; then
>  		options="$options -Dexamples=all"
> diff --git a/lib/meson.build b/lib/meson.build
> index fac2f52cad..73afd90b38 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -93,6 +93,15 @@ dpdk_libs_deprecated += [
>          'kni',
>  ]
>  
> +enable_deprecated_libs = []
> +foreach l:run_command(list_dir_globs, get_option('enable_deprecated_libs'),
> +        check: true).stdout().split()
> +    if not dpdk_libs_deprecated.contains(l)
> +        continue
> +    endif
> +    enable_deprecated_libs += l
> +endforeach
> +
>  disabled_libs = []
>  opt_disabled_libs = run_command(list_dir_globs, get_option('disable_libs'),
>          check: true).stdout().split()
> @@ -137,16 +146,19 @@ foreach l:libraries
>          deps += ['eal']
>      endif
>  
> -    if disabled_libs.contains(l)
> -        build = false
> -        reason = 'explicitly disabled via build config'
> -        if dpdk_libs_deprecated.contains(l)
> -            reason += ' (deprecated lib)'
> -        endif
> -    else
> -        if dpdk_libs_deprecated.contains(l)
> +    if dpdk_libs_deprecated.contains(l)
> +        if not enable_deprecated_libs.contains(l)
> +            build = false
> +            reason = 'not in enabled deprecated libraries build config'
> +        else
>              warning('Enabling deprecated library, "@0@"'.format(l))
>          endif
> +    elif disabled_libs.contains(l)
> +        build = false
> +        reason = 'explicitly disabled via build config'
> +    endif
> +
> +    if build
>          subdir(l)
>      endif
>      if name != l
> diff --git a/meson_options.txt b/meson_options.txt
> index 82c8297065..839d4266c6 100644
> --- a/meson_options.txt
> +++ b/meson_options.txt
> @@ -10,7 +10,7 @@ option('disable_apps', type: 'string', value: '', description:
>         'Comma-separated list of apps to explicitly disable.')
>  option('disable_drivers', type: 'string', value: '', description:
>         'Comma-separated list of drivers to explicitly disable.')
> -option('disable_libs', type: 'string', value: 'flow_classify,kni', description:
> +option('disable_libs', type: 'string', value: '', description:
>         'Comma-separated list of libraries to explicitly disable. [NOTE: not all libs can be disabled]')
>  option('drivers_install_subdir', type: 'string', value: 'dpdk/pmds-<VERSION>', description:
>         'Subdirectory of libdir where to install PMDs. Defaults to using a versioned subdirectory.')
> @@ -18,6 +18,8 @@ option('enable_docs', type: 'boolean', value: false, description:
>         'build documentation')
>  option('enable_apps', type: 'string', value: '', description:
>         'Comma-separated list of apps to build. If unspecified, build all apps.')
> +option('enable_deprecated_libs', type: 'string', value: '', description:
> +       'Comma-separated list of deprecated libraries to explicitly enable.')
>  option('enable_drivers', type: 'string', value: '', description:
>         'Comma-separated list of drivers to build. If unspecified, build all drivers.')
>  option('enable_driver_sdk', type: 'boolean', value: false, description: