Allow compilation against older atspi-2 versions

Since atspi-2 does not support getting version information at compile
time, we must do this manually with pkg-config. Add defines for the
versions of atspi-2 that we care about and guard newer enum values with
those defines.

Bug: 887908
Change-Id: I8eecb2eeada48cc2176117b764adbf77b26ce351
Reviewed-on: https://chromium-review.googlesource.com/c/1238437
Commit-Queue: Martin Robinson <mrobinson@igalia.com>
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598863}

build/config/linux/BUILD.gn

@@ -103,6 +103,20 @@ if (use_glib) {
 if (use_atk) {
   pkg_config("atspi2") {
     packages = [ "atspi-2" ]
+    atspi_version = exec_script(pkg_config_script,
+                                pkg_config_args + [
+                                      "atspi-2",
+                                      "--version-as-components",
+                                    ],
+                                "value")
+    atspi_major_version = atspi_version[0]
+    atspi_minor_version = atspi_version[1]
+    atspi_micro_version = atspi_version[2]
+    defines = [
+      "ATSPI_MAJOR_VERSION=$atspi_major_version",
+      "ATSPI_MINOR_VERSION=$atspi_minor_version",
+      "ATSPI_MICRO_VERSION=$atspi_micro_version",
+    ]
   }
 }
 

build/config/linux/pkg-config.py

@@ -124,6 +124,8 @@ def main():
                     dest='atleast_version', type='string')
   parser.add_option('--libdir', action='store_true', dest='libdir')
   parser.add_option('--dridriverdir', action='store_true', dest='dridriverdir')
+  parser.add_option('--version-as-components', action='store_true',
+                    dest='version_as_components')
   (options, args) = parser.parse_args()
 
   # Make a list of regular expressions to strip out.
@@ -151,6 +153,17 @@ def main():
       print "false"
     return 0
 
+  if options.version_as_components:
+    cmd = [options.pkg_config, "--modversion"] + args
+    try:
+      version_string = subprocess.check_output(cmd)
+    except:
+      sys.stderr.write('Error from pkg-config.\n')
+      return 1
+    print json.dumps(list(map(int, version_string.strip().split("."))))
+    return 0
+
+
   if options.libdir:
     cmd = [options.pkg_config, "--variable=libdir"] + args
     if options.debug: