[dpdk-dev] [PATCH] build: fix compatibility with meson 0.41 onwards

[Bruce Richardson <bruce.richardson@intel.com>]

Versions of meson prior to 0.47 flattened the parameters to the
"set_variable" function, which meant that the function could not take
array variables as a parameter. Therefore, we need to disable driver
tracking for those older versions, in order to maintain compatibility
with the minimum supported 0.41 version, and also v0.45 shipped in
Ubuntu 18.04 release.

Fixes: 806c45dd483d ("build: add configuration summary at end of config")

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 drivers/meson.build |  5 ++++-
 meson.build         | 33 +++++++++++++++++++--------------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/meson.build b/drivers/meson.build
index b6ce974de..c5df313dd 100644
--- a/drivers/meson.build
+++ b/drivers/meson.build
@@ -145,5 +145,8 @@ foreach class:driver_classes
 		endif # build
 	endforeach
 
-	set_variable(class + '_drivers', class_drivers)
+	if meson.version().version_compare('>=0.47')
+		# prior to 0.47, set_variable can't take array params
+		set_variable(class + '_drivers', class_drivers)
+	endif
 endforeach
diff --git a/meson.build b/meson.build
index 7332e75b5..2ed1247a3 100644
--- a/meson.build
+++ b/meson.build
@@ -89,18 +89,23 @@ foreach lib:enabled_libs
 endforeach
 message(output_message + '\n')
 
-output_message = '\n===============\nDrivers Enabled\n===============\n'
-foreach class:driver_classes
-	class_drivers = get_variable(class + '_drivers')
-	output_message += '\n' + class + ':\n\t'
-	output_count = 0
-	foreach drv:class_drivers
-		output_message += drv + ', '
-		output_count += 1
-		if output_count == 8
-			output_message += '\n\t'
-			output_count = 0
-		endif
+
+# prior to 0.47 set_variable didn't work with arrays, so we can't
+# track driver lists easily
+if meson.version().version_compare('>=0.47')
+	output_message = '\n===============\nDrivers Enabled\n===============\n'
+	foreach class:driver_classes
+		class_drivers = get_variable(class + '_drivers')
+		output_message += '\n' + class + ':\n\t'
+		output_count = 0
+		foreach drv:class_drivers
+			output_message += drv + ', '
+			output_count += 1
+			if output_count == 8
+				output_message += '\n\t'
+				output_count = 0
+			endif
+		endforeach
 	endforeach
-endforeach
-message(output_message + '\n')
+	message(output_message + '\n')
+endif
-- 
2.17.1